JP5832080B2 - Power generation system control device, power generation system, and power generation system control method - Google Patents

Description

  The present invention relates to a power generation system control device, a power generation system, and a power generation system control method.

  In a thermal power plant or the like, many power generation systems including a furnace and a steam turbine as main components are employed. As this power generation system, the steam generated in the furnace is further heated by a superheater, and the flow rate of this superheated steam is adjusted by a turbine governor and supplied to the steam turbine, and the steam is used to generate power. There is something.

For such a power generation system, Patent Document 1 provides a first steam pipe that connects the furnace and the superheater, a second steam pipe that connects the superheater and the steam turbine, and a first steam pipe. In addition, a power generation system including a first valve, a turbine governor provided in a second steam pipe, and a control unit that adjusts the opening of the first valve according to the load of the steam turbine is described.
According to the power generation system described in Patent Literature 1, since the steam pressure is adjusted to a value corresponding to the load of the steam turbine on the upstream side of the superheater, the operation of the turbine governor installed on the downstream side of the superheater. The width can be reduced, and when the turbine governor is operated, it is possible to prevent the steam temperature from being lowered by the adiabatic expansion that occurs on the downstream side of the turbine governor. As a result, the efficiency of the steam turbine can be improved. Furthermore, since there is no restriction on the operation width of the turbine governor and the flow rate of the steam flowing into the steam turbine can be freely adjusted, it is possible to improve the followability to the required power generation amount of the steam turbine.

JP 2008-248808 A

In addition, the power generation system may include a plurality of water supply pumps that supply water to the furnace. In such a power generation system, the amount of water supplied to the furnace is increased or decreased by increasing or decreasing the number of water supply pumps that supply water to the furnace as the load on the steam turbine increases or decreases.
However, in a power generation system including a plurality of feed water pumps in the conventional (constant-pressure once-through) power generation system described in Patent Document 1, when a new feed water pump is rotated to feed water to the furnace, the amount of feed water is set to a steady state. A waiting time was required, and it was difficult to continuously switch the feed water pump in a short time as the load increased or decreased.

  The present invention has been made in view of such circumstances, and even when the number of water supply pumps for supplying water to the furnace is increased or decreased as the load increases or decreases, a short time between a low load and a high load is achieved. It is an object of the present invention to provide a power generation system control device, a power generation system, and a power generation system control method that can be continuously changed.

In order to solve the above-described problems, a power generation system control device, a power generation system, and a power generation system control method of the present invention employ the following means.
That is, the control device of the power generation system according to the present invention includes a furnace that combusts fuel and generates steam by the heat of the combustion, a steam turbine that rotates by the steam generated by the furnace, and a plurality of water supplies to the furnace A feed water pump, and a steam turbine output target value in a state where water is supplied to the furnace using a predetermined water pump among the plurality of water pumps. Exceeds the first preset value, and when the load of the steam turbine reaches the preset first value, the other feed water pump is rotated to a rotational speed at which water can be supplied to the furnace. And when the output target value exceeds a preset second set value and the load reaches a preset second value higher than the first value, the other feed pump Also for And performing first control for starting the water supply to the furnace.

According to the present invention, a power generation system includes a furnace that combusts fuel and generates steam by the heat of the combustion, a steam turbine that rotates by steam generated by the furnace, a plurality of feed pumps that supply water to the furnace, It has.
Note that the number of the feed water pumps to be driven increases as the load of the steam turbine increases.
Then, in a state where water is supplied to the furnace using a predetermined feed water pump, the output target value of the steam turbine exceeds a preset first set value, and the load of the steam turbine is preset. When the value of 1 is reached, the other feed water pump is rotated to a rotation speed at which water can be supplied to the furnace, the output target value exceeds the preset second set value, and the load is greater than the first value. When the second preset higher value is reached, the other water supply pump starts water supply to the furnace.
Conventionally, the rotation of the other water supply pump is started manually by the operator, and the water supply to the furnace is started manually after the increase of the load is completed and the water supply amount is in a settling state. It was. That is, even if a higher load is required, the power generation system cannot increase the load until the amount of water supplied by the other water supply pump is in a steady state.
On the other hand, in the present invention, the first value and the second value are set in advance, and when the load of the steam turbine reaches the first value, the rotation of the feed water pump is started, and the load of the steam turbine is set to the second value. When this value is reached, water supply to the furnace is started by the water supply pump, so that the load of the steam turbine increases without requiring a waiting time for the settling state. For this reason, this invention can change continuously between a low load and a high load for a short time, even when it is a case where the number of water supply pumps which supply water to a furnace is increased / decreased with increase / decrease in load.

Further, the control device of the power generation system of the present invention is configured in advance when the load is reduced to a preset third value in a state where water is supplied to the furnace using the plurality of water supply pumps. Decreasing and stopping the water supply to the furnace by the set water pump, and reducing the rotation of the water pump when the load reaches a preset fourth value lower than the third value The second control may be performed.
According to the present invention, when water is supplied to the furnace using a plurality of feed water pumps, when the load of the steam turbine is reduced to a preset third value, the preset feed water pump When the water supply to the furnace is stopped and the load reaches a preset fourth value lower than the third value, the rotation of the water supply pump is reduced.
Thus, according to the present invention, when the third value and the fourth value are set in advance and the load reaches the third value, the water supply to the furnace by the preset water pump is stopped, and the load is reduced. When the fourth value is reached, the rotation of the water supply pump is reduced, so that the load can be continuously reduced in a short time.

In the power generation system control device according to the present invention, the power generation system is provided for each deaerator for degassing the water supplied to the feed water pump and the feed water pump, and is supplied with pressure from the feed water pump. A pipe that leads the feed water to the deaerator, and a valve that is provided for each pipe and that is opened when the amount of feed water pumped by the feed pump is larger than the load; and It is desirable that the valve be closed from the viewpoint of water supply control when the first control is performed.
According to the present invention, it is possible to prevent the amount of water supplied from the water supply pump to the furnace from becoming unstable by keeping the valve closed while the control of switching of the water supply pump is being performed.

Further, in the control device for the power generation system of the present invention, the bearing oil temperature of the rotating shaft before the first control of the other feed pump is performed, the first control is performed, and the load of the steam turbine is the Between reaching the second value from the first value, it is necessary to reach a predetermined temperature that enables water supply to the furnace.
According to the present invention, it becomes possible to set the bearing oil temperature of the rotating shaft of the other feed water pump before the first control to be higher, so that the other feed water pump can be fed to the furnace earlier. It can be made.

The power generation system according to the present invention includes a furnace that combusts fuel and generates steam by the heat of the combustion, a steam turbine that generates power by rotating a turbine using the steam generated by the furnace, and A plurality of water supply pumps for supplying water to the furnace and the control device described above are provided.
According to the present invention, since the above-described control device is provided, even when the number of water supply pumps for supplying water to the furnace is increased or decreased as the load increases or decreases, the load between the low load and the high load is continuously reduced in a short time. Can be changed.

Further, the power generation system of the present invention is provided between the furnace and the steam turbine, and a superheater that superheats steam, a first steam pipe that connects the furnace and the superheater, and the superheater, The second steam pipe connecting the steam turbine, the first valve provided in the first steam pipe, the turbine governor provided in the second steam pipe, and the load according to the load of the steam turbine And a control means for adjusting the opening degree of the first valve.
According to the present invention, since the steam pressure is adjusted to a value corresponding to the load of the steam turbine on the upstream side of the superheater, the operating width of the turbine governor installed on the downstream side of the superheater can be reduced. In addition, when the turbine governor is operated, it is possible to prevent the steam temperature from being lowered due to the adiabatic expansion that occurs on the downstream side of the turbine governor. As a result, the efficiency of the steam turbine can be improved. Furthermore, since there is no restriction on the operating width of the turbine governor and the flow rate of the steam flowing into the steam turbine can be freely adjusted, the followability to the required power generation amount of the steam turbine can be improved.

The power generation system control method according to the present invention includes a furnace that burns fuel and generates steam by the heat of the combustion, a steam turbine that rotates by the steam generated by the furnace, and a plurality of water supplies to the furnace A feed water pump, and a steam turbine output target value in a state where water is supplied to the furnace using a predetermined water pump among the plurality of water pumps. Exceeds the first preset value, and when the load of the steam turbine reaches the preset first value , the other feed water pump is rotated to a rotational speed at which water can be supplied to the furnace. And when the output target value exceeds a preset second set value and the load reaches a preset second value higher than the first value , the other feed pump Also used Serial to start the water supply to the furnace.
According to the present invention, when the load of the steam turbine reaches the first value, the rotation of the feed water pump is started, and when the load of the steam turbine reaches the second value, water supply to the furnace by the feed water pump is started. Therefore, the load on the steam turbine increases without requiring a waiting time for the settling state. For this reason, this invention can change continuously between a low load and a high load for a short time, even when it is a case where the number of water supply pumps which supply water to a furnace is increased / decreased with increase / decrease in load.

  According to the present invention, even when the number of feed pumps for supplying water to the furnace is increased or decreased as the load increases or decreases, it is possible to continuously change the load between a low load and a high load in a short time. It has the effect.

It is a figure which shows the structure of the electric power generation system which concerns on embodiment of this invention. It is a figure required for description of switching control of the conventional turbine drive type water supply pump. It is a block diagram which shows the flow of the process of the control for raising the speed of the turbine drive type water supply pump which concerns on embodiment of this invention. It is a block diagram which shows the flow of the process of the control for in-service the turbine drive type water supply pump which concerns on embodiment of this invention. It is a figure required for description of the output target value and output command value concerning the embodiment of the present invention. It is a figure required for description of the setting of the opening degree of the recirculation valve which concerns on embodiment of this invention. It is a graph which shows the increase change of the load of the steam turbine which concerns on embodiment of this invention. It is a block diagram which shows the flow of the process of the control for making a turbine drive type feed water pump which concerns on embodiment of this invention out-service. It is a block diagram which shows the flow of the process of the control for decelerating the turbine drive type feed water pump which concerns on embodiment of this invention. It is a graph which shows the reduction | decrease change of the load of the steam turbine which concerns on embodiment of this invention.

  Hereinafter, an embodiment of a power generation system control device, a power generation system, and a power generation system control method according to the present invention will be described with reference to the drawings.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
In FIG. 1, a power generation system 1 includes a furnace 2 that burns liquid fuel (for example, LNG (Liquid Natural Gas)) and generates steam by the heat of the combustion, and a water pipe (not shown) provided in the furnace 2. A boiler circulation pump 3 for circulating water, a steam turbine 4 for generating power by driving a generator (not shown) by rotating the turbine using steam generated by the furnace 2, a furnace 2 and a steam turbine 4, And a superheater 7 that superheats steam.
Furthermore, the power generation system 1 is provided in a first steam pipe 11 that connects the furnace 2 and the superheater 7, a second steam pipe 12 that connects the superheater 7 and the steam turbine 4, and the first steam pipe 11. Boiler throttle valve 15, turbine governor 17 provided in second steam pipe 12, third steam pipe 13 connected to first steam pipe 11 and bypassing boiler throttle valve 15, and third steam pipe 13 The provided boiler throttle bypass valve 16 and a controller (not shown) that adjusts the opening of the boiler throttle valve 15 and the boiler throttle bypass valve 16 according to the load of the steam turbine 4 are provided.

In the present embodiment, the steam turbine 4 includes a high-pressure steam turbine 4a and a low / medium-pressure steam turbine 4b, and the steam discharged from the high-pressure steam turbine 4a passes through the reheater 20 to the low / medium-pressure steam turbine. 4b is supplied.
Moreover, the superheater 7 is provided with the 1st superheater 7a provided in the upstream, and the 2nd superheater 7b provided in the downstream, The vapor | steam which distribute | circulates between the 1st superheater 7a and the 2nd superheater 7b. A temperature reducer 9 is provided to reduce the temperature.

The water overheating cycle in the power generation system having the above configuration will be described below.
In the furnace 2, liquid fuel is combusted, and steam is generated by starting the boiler circulation pump 3 and circulating water through a water pipe provided in the furnace 2. The steam generated in the furnace 2 is guided to the first superheater 7a. In the first superheater 7a, the steam is superheated, and the steam superheated in the first superheater 7a is guided to the temperature reducer 9. The temperature reducer 9 lowers the temperature of the steam by injecting water. The steam reduced in temperature by the temperature reducer 9 is guided to the second superheater 7b and reheated again by the second superheater 7b. The steam reheated by the second superheater 7b is adjusted in flow rate by the turbine governor 17 and introduced into the high-pressure steam turbine 4a, and used to drive the high-pressure steam turbine 4a.

  The steam after driving the high-pressure steam turbine 4 a is led to the reheater 20 and is reheated again by the reheater 20. The steam superheated again by the reheater 20 is introduced into the low and medium pressure steam turbine 4b and used to drive the low and medium pressure steam turbine 4b.

The steam after driving the low intermediate pressure steam turbine 4 b is guided to the condenser 21 and returned to water (liquid) by the condenser 21. The water generated in the condenser 21 is pumped by the condensate pump 22 in the order of the low-pressure feed water superheater 23 and the deaerator 24. The water deaerated by the deaerator 24 is pumped to the high-pressure feed water superheater 26 by the boiler feed pump 25 and pumped to the temperature reducer 9 and the economizer 28.
In the temperature reducer 9, the temperature of the steam is controlled by injecting water into the steam. However, in order to inject water, the feed water pressure needs to be higher than the steam pressure. Therefore, the pressure of the water supplied to the temperature reducer 9 is maintained higher than the steam pressure by opening and closing the movable nozzle 27.
The water pressure-fed to the temperature reducer 9 through the superheater spray pressure adjustment valve 29 and the superheater spray adjustment valve 30 is used to lower the temperature of the steam. Moreover, the water pumped to the economizer 28 is guided to the furnace 2 by the boiler circulation pump 3 and is used again as steam.

In the power generation system 1 according to the present embodiment, when the power generation system 1 is started, the boiler throttle bypass valve 16 is opened and the steam generated in the furnace 2 is circulated through the third steam pipe 13. At this time, the boiler throttle bypass valve 16 is not fully opened, and is set to an opening degree (for example, 50%) such that the steam pressure _{PT at the} inlet portion of the turbine governor 17 does not rapidly increase. At this time, the boiler throttle bypass is set so that the differential pressure between the steam pressure P _{WWO at the} outlet of the furnace 2 and the steam pressure _PT at the inlet of the turbine governor 17 is within the allowable differential pressure of the boiler throttle valve 15. The opening degree of the valve 16 is adjusted.

Next, when the ratio to the rated load is equal to or higher than the first threshold (for example, 40%), the boiler throttle valve 15 is controlled while controlling the steam pressure _{PT so} that there is no fluctuation by the boiler throttle bypass valve 16. It opens to a certain degree of opening (for example, 10%), and the steam generated in the furnace 2 is circulated through the first steam pipe 11.
Next, the opening degree of the boiler throttle valve 15 and the boiler throttle bypass valve 16 is adjusted according to the load until the ratio to the rated load is less than a second threshold value (for example, 75%). At this time, the steam pressure _{PT at the} inlet portion of the turbine governor 17 gradually reaches the maximum pressure (for example, 24 MPa) determined by the specifications of the furnace 2, and the front-rear differential pressure of the boiler throttle valve 15 is the allowable differential pressure. So that the opening degree of the boiler throttle valve 15 and the boiler throttle bypass valve 16 is adjusted.

  As described above, by adjusting the opening degree of the boiler throttle valve 15 and the boiler throttle bypass valve 16, the steam pressure in the turbine governor 17 can be set to a pressure corresponding to the turbine load. The adjustment amount of the steam flow rate can be reduced. That is, the opening degree of the turbine governor 17 with respect to the load fluctuation of the high-pressure steam turbine 4a can be gradually changed.

As described above, in the power generation system 1 according to the present embodiment, the steam pressure is adjusted to the pressure corresponding to the load of the high-pressure steam turbine 4a on the upstream side of the turbine governor 17, so that the operation width of the turbine governor 17 is reduced. can do. Thereby, when the turbine governor 17 is operated, the pressure loss generated on the downstream side of the turbine governor 17 can be reduced. As a result, the efficiency of the high pressure steam turbine 4a can be improved.
Moreover, since the temperature change of the steam flowing into the high-pressure steam turbine 4a can be reduced by reducing the operation width of the turbine governor 17, the life of the high-pressure steam turbine 4a can be extended. Furthermore, since the restriction on the operation width of the turbine governor 17 is reduced and the flow rate of the steam flowing into the high-pressure steam turbine 4a can be freely adjusted, the followability of the high-pressure steam turbine 4a with respect to the required power generation can be improved.

  Further, the steam pipe connecting the furnace 2 with the boiler throttle valve 15 and the boiler throttle bypass valve 16 is branched. The branched steam pipe is connected to the condenser 21 via the brackish water separator 33. The steam pipe is provided with a boiler start bleed valve 34, and further includes a steam pipe that bypasses the boiler start bleed valve 34 and is provided with a boiler start bleed bypass valve 35. The steam pipe connecting the brackish water separator 33 and the condenser 21 is provided with a starting separator drain adjustment valve 36.

Furthermore, the power generation system 1 according to the present embodiment includes turbine-driven feed water pumps 25T1 and 25T2 and an electrically-driven feed water pump 25M as the boiler feed water pump 25.
The turbine-driven feed water pumps 25T1 and 25T2 are driven by the boiler feed water pump driving steam turbine 37 being rotated. The steam turbine 37 for driving the boiler feed pump is driven by supplying the steam exhausted from the second superheater 7b and the steam extracted from the low intermediate pressure steam turbine 4b after the flow rate is adjusted by the governor 38. To do. On the other hand, the electrically driven feed water pump 25M is driven by a rotational drive of a motor (not shown).
Further, the water supply pipes connecting the turbine-driven feed water pumps 25T1 and 25T2 and the electric drive-type feed water pump 25M and the high-pressure feed water superheater 26 are respectively branched and connected to the deaerator 24 via the recirculation valve 39. Yes. For this reason, when the flow rate discharged from the turbine-driven feed water pumps 25T1 and 25T2 is larger than the load of the steam turbine 4, the feedwater from the turbine-driven feedwater pumps 25T1 and 25T2 can be returned to the deaerator 24. Has been.

The turbine-driven feed water pumps 25T1 and 25T2, the electrically-driven feed water pump 25M, and the recirculation valves 39 are controlled by a boiler feed pump control device 40a and an APC (Automatic Plant Control) control device 40b. The boiler feed pump control device 40a and the APC control device 40b control the start and stop of the turbine driven feed water pumps 25T1 and 25T2 and the electrically driven feed water pump 25M and the opening degree of the recirculation valve 39.
More specifically, the boiler feed pump control device 40a and the APC control device 40b are configured to start power generation by the power generation system 1, that is, when the load of the steam turbine 4 is small (for example, 0 to 15% of the rated load). Then, the electrically driven feed water pump 25M is driven, and water is supplied to the furnace 2 only by the electrically driven feed water pump 25M. The turbine-driven feed water pumps 25T1 and 25T2 are driven using steam supplied to the steam turbine 4 or steam supplied from the steam turbine 4, so that when the power generation of the power generation system 1 is started, the drive is performed by its own boiler. Cannot start with generated steam.
And when the load of the steam turbine 4 becomes large (for example, 15% or more of the rated load), the boiler feed pump control device 40a and the APC control device 40b drive one of the turbine-driven feed water pumps 25T1 and 25T2, Supply water to the furnace 2. At this time, the electrically driven feed water pump 25M is stopped. Further, which of the turbine-driven feed water pumps 25T1 and 25T2 is driven is determined in advance by the total operation time of the turbine-driven feed water pumps 25T1 and 25T2.
When the load of the steam turbine 4 is further increased, the boiler feed pump control device 40a and the APC control device 40b further drive the turbine drive type feed pumps that are not driven, that is, drive both the turbine drive type feed pumps 25T1 and 25T2. And water is supplied to the furnace 2.
On the other hand, when the load of the steam turbine 4 is reduced, the boiler feed pump control device 40a and the APC control device 40b stop driving one of the turbine-driven feed water pumps 25T1 and 25T2, and further stop the power generation of the power generation system 1. In this case, the driving of the turbine-driven feed water pump that is being driven is stopped, while the electrically driven feed water pump 25M is driven, and in the stopping process, the drive of the electrically driven feed water pump 25M is also stopped.
In the following description, a load (for example, 15% of the rated load) when water supply to the furnace 2 is started using any one of the turbine-driven feed water pumps 25T1 and 25T2 is referred to as a minimum load.

Here, with reference to FIG. 2, switching (switching control) of the turbine-driven feed water pump in the conventional (constant pressure once-through) power generation system described in Patent Document 1 will be described.
As an example, FIG. 2 shows that one turbine-driven feed water pump is driven when the load is 90 MW to 300 MW (50% of the rated load), and the turbine is driven when the load is 300 MW to 600 MW (100% of the rated load). The change of the load of the conventional steam turbine which drives 2 type | mold water pumps is shown.
When the conventional power generation system increases the load at a stroke from 90 MW, which is the minimum load for driving the turbine-driven feed water pump, to 600 MW, which is the rated load, before the load exceeds 300 MW, The second turbine-driven feed water pump was started to accelerate, and after the water supply amount reached a steady state at 300 MW, water supply to the furnace was started by the turbine-driven feed water pump. Therefore, in the conventional power generation system, it is necessary to maintain the load as 300 MW for a predetermined time (for example, 20 minutes) until the second turbine-driven feed water pump is settled. Could not be raised.

In addition, the ascending speed of the turbine-driven feed water pump is to rotate the rotating body of the turbine-driven feed water pump to a rotational speed at which water can be supplied (hereinafter referred to as “water supply standby rotational speed”). In the ascending state, no water is supplied to the furnace.
On the other hand, setting the rotational speed of the rotating body of the turbine-driven water supply pump to a predetermined rotational speed that is equal to or lower than the water supply standby rotational speed is referred to as speed reduction.
Further, in the following description, starting water supply to the furnace with the accelerated turbine-driven feed water pump is referred to as in-service, and reducing and stopping water supply to the furnace with the turbine-driven feed water pump is referred to as out-service.

  Next, switching control of the turbine-driven feed water pumps 25T1 and 25T2 in the power generation system 1 according to the present embodiment will be described.

Hereinafter, in the power generation system 1 according to the present embodiment, a case where the turbine-driven feedwater pump 25T2 is in-service while the turbine-driven feedwater pump 25T1 is being driven will be described.
FIG. 3 is a function showing the flow of switching control processing in the boiler feed pump control device 40a for increasing the speed of the turbine drive feed pump T2 in order to bring the turbine drive feed pump 25T2 that is not driven into service. It is a block diagram.
As shown in FIG. 3, the boiler feed pump control device 40 a includes an output target value input unit 50, a generator total power input unit 51, and a condition determination unit 52.

The output target value input unit 50 receives the target value of the output (load) of the steam turbine 4 transmitted from the central power supply command station. The total power generation amount generated by the generator included in the power generation system 1 is input to the generator total power input unit 51. The total values input to the output target value input unit 50 and the generator total power input unit 51 are compared with the set values input to the comparison units 53A and 53B, respectively.
For example, 175 MW is input as a setting value to the comparison unit 53A. The comparison unit 53A outputs an ON signal to the AND gate 54 when the target value input to the output target value input unit 50 exceeds the set value, while the target input to the output target value input unit 50. When the value is less than or equal to the set value, an off signal is output to the AND gate 54.
For example, 150 MW is input as a setting value to the comparison unit 53B. When the total value input to the generator total power input unit 51 exceeds the set value, the comparison unit 53B outputs an ON signal to the AND gate 54 while being input to the generator total power input unit 51. When the total value is less than or equal to the set value, an OFF signal is output to the AND gate 54.

The condition determination unit 52 determines whether or not the power generation system 1 satisfies various predetermined conditions for increasing the speed of the turbine-driven feed water pump 25T2, and determines that the various conditions are satisfied. In this case, an ON signal is output to the AND gate 54, while an OFF signal is output to the AND gate 54 when it is determined that various conditions are not satisfied.
The various conditions include, for example, a condition that the temperature difference between each part of the turbine-driven feed water pump 25T2 and the metal temperature are a predetermined temperature.

  The AND gate 54 outputs an ON signal to the speed increase command output unit 55 when all the input signals are ON signals. When the ON signal output from the AND gate 54 is input, the speed increase command output unit 55 outputs the ON signal to the notification processing unit 56 (for example, after 10 seconds) and then increases to the turbine-driven feed water pump 25T2. The speed command value is output.

  When the ON signal is input, the notification processing unit 56 notifies the operator by voice that the turbine-driven feed water pump 25T2 starts to accelerate from the speaker provided in the operation unit 57. Note that the notification processing unit 56 may display an image indicating that the turbine-driven feed water pump 25T2 starts increasing the speed on the monitor of the operation unit 57.

  On the other hand, when the speed increase command value output from the speed increase command output unit 55 is input, the turbine-driven water supply pump 25T2 starts speed increase, and when the rotational speed of the rotating body reaches the water supply standby speed, The rotating body is maintained at the rotation speed. That is, in the power generation system 1 according to the present embodiment, when the load of the steam turbine 4 exceeds 150 MW, the turbine-driven feed water pump 25T2 starts to accelerate. In the following description, the load for starting the acceleration, that is, the set value input to the comparison unit 53B is referred to as the acceleration start load.

On the other hand, FIG. 4 is a block diagram showing a flow of processing of switching control for in-service the increased turbine-driven feed water pump 25T2.
As shown in FIG. 4, the APC control device 40 b includes an output target value input unit 60, an output command value input unit 61, a BFP interlocking value input unit 62, and a condition determination unit 63.
In addition, the target value of the load of the steam turbine 4 transmitted from the central power supply command station is input to the output target value input unit 60. The change rate of the load of the steam turbine 4 is input to the output command value input unit 61.

Here, the output target value and the output command value will be described with reference to FIG.
As described above, the output target value is the target value of the load of the steam turbine 4 transmitted from the central power supply command station, and is constant as shown by the solid line in FIG. On the other hand, the output command value is a command value that changes with time with the output target value as a maximum value for gradually increasing the load of the steam turbine 4, and has a predetermined change as shown by a one-dot chain line in FIG. 5. It has a rate (slope).
Then, when the power generation system 1 receives the output target value transmitted from the central power supply command station, the power generation system 1 generates an output command value corresponding to the output target value, and operates so as to operate with a load corresponding to the output command value. The turbine 4 is driven.

Then, the command values input to the output target value input unit 60 and the output command value input unit 61 are compared with the set values input to the comparison units 64A and 64B, respectively.
For example, 245 MW is input as a setting value to the comparison unit 64A. The comparison unit 64A outputs an ON signal to the AND gate 65 when the target value input to the output target value input unit 60 exceeds the set value, while the target input to the output target value input unit 60. When the value is less than the set value, an OFF signal is output to the AND gate 65.
For example, 215 MW is input as a setting value to the comparison unit 64B. The comparison unit 64B outputs an ON signal to the AND gate 65 when the command value input to the output command value input unit 61 exceeds the set value, while the command input to the output command value input unit 61. When the value is less than the set value, an OFF signal is output to the AND gate 65.
Note that the set value input to the comparison units 64A and 64B is set higher than the acceleration start load.

  On the other hand, in the BFP interlocking value input unit 62, when the speed increase of the turbine-driven water supply pump 25T2 is completed, a signal indicating that the speed increase is completed, a bearing of the rotating shaft of the rotating body of the turbine-driven water supply pump 25T2 When the oil temperature is a predetermined temperature (for example, 38 ° C.) described later, an input of a signal indicating that the oil temperature is the predetermined temperature is accepted, and when all of these signals are input, the turbine drive type An ON signal indicating that the water pump 25T2 is in service is output to the AND gate 65. On the other hand, if any one of the above signals is not input, an OFF signal is output to the AND gate 65. .

The condition determination unit 63 determines whether or not the power generation system 1 satisfies various predetermined conditions for in-service of the turbine-driven feed water pump 25T2, and determines that the various conditions are satisfied. In this case, an ON signal is output to the AND gate 65, while an OFF signal is output to the AND gate 65 when it is determined that various conditions are not satisfied.
The various conditions include, for example, conditions that each recirculation valve 39 is not in the manual control mode and that the unit operation mode is in the cooperative control mode.

  The AND gate 65 outputs an ON signal to the in-service command output unit 66 when all the input signals are ON signals. When the ON signal output from the AND gate 65 is input, the in-service command output unit 66 outputs the ON signal to the notification processing unit 56 (for example, after 10 seconds), and then enters the turbine-driven feed water pump 25T2. The service command value is output.

  When the ON signal is input, the notification processing unit 56 notifies the operator by voice that the turbine-driven water supply pump 25T2 starts in-service from the speaker provided in the operation unit 57. Note that the notification processing unit 56 may display an image indicating that the turbine-driven feed water pump 25T2 starts in-service on the monitor of the operation unit 57.

  On the other hand, when the in-service command value output from the in-service command output unit 66 is input, the turbine-driven feed water pump 25T2 starts water supply to the furnace 2. That is, in the power generation system 1 according to the present embodiment, in-service of the turbine-driven feed water pump 25T2 is started when the load of the steam turbine 4 exceeds 215 MW. In the following description, a load for starting in-service, that is, a set value input to the comparison unit 64B is referred to as in-service start load.

Moreover, in the electric power generation system 1 which concerns on this embodiment, when switching control of turbine drive type feed water pump 25T1, T2 is performed, the recirculation valve 39 is made into a closed state.
Specifically, the opening degree of the recirculation valve 39 according to this embodiment is set according to the suction flow rate of the turbine-driven feed water pumps 25T1 and T2, but as shown in an example of FIG. There may be a case where the value of the suction flow rate at which the valve 39 is opened is changed in a direction to lower the value within a range allowed by the turbine-driven feed water pumps 25T1 and T2. In the example of FIG. 6, when the suction flow rate is 375 ton / hour or less for the turbine-driven feed water pumps 25T1 and 25T2, the recirculation valve 39 has started to open, and the suction flow rate is 320 ton / hour or less. In this case, the opening degree of the recirculation valve 39 is set so that the recirculation valve 39 starts to open, and the recirculation valve 39 becomes difficult to open.
Thereby, in the power generation system 1 according to the present embodiment, the amount of water supplied from the turbine-driven feed water pumps 25T1 and T2 to the furnace 2 in a state where the switching control is performed by changing the opening degree of the recirculation valve 39. Can be prevented from becoming unstable. The opening degree of the recirculation valve 39 is set by the APC control device 40b.

Further, in the power generation system 1 according to the present embodiment, the temperature of the bearing oil of the rotating shaft of the turbine-driven feed water pump 25T2 before the switching control is performed is switched, and the load of the steam turbine 4 is the acceleration start load. Until the in-service start load is reached, the temperature is set to reach a predetermined temperature at which water can be supplied to the furnace 2. The predetermined temperature at which water can be supplied to the furnace 2 is, for example, 38 ° C.
That is, in the conventional power generation system, the bearing oil temperature of the rotating shaft of the turbine-driven feed water pump at the time of falling is set at, for example, 32 ° C., and it takes time to reach the predetermined temperature (38 ° C.). It was. However, in the power generation system 1 according to the present embodiment, the bearing oil temperature of the rotating shaft of the turbine-driven feed water pump 25T2 at the time of descending speed is set to 35 ° C., for example. Thereby, since the bearing oil temperature of a rotating shaft reaches the said predetermined temperature (38 degreeC) more reliably before the load of the steam turbine 4 reaches an in-service start load from an acceleration start load, The turbine-driven feed water pump 25T2 can be supplied to the furnace 2.

FIG. 7 is a graph showing an increasing change in the operational load in the power generation system 1 according to the present embodiment.
In the power generation system 1 according to this embodiment, the acceleration start load and the in-service start load are set in advance, and when the operation load of the steam turbine 4 reaches the acceleration start load, the rotation of the turbine-driven feed water pump 25T2 starts. When the operation load of the steam turbine 4 reaches the in-service start load, water supply to the furnace 2 by the turbine-driven feed water pump 25T2 is started, so the load increases without requiring a waiting time for the settling state. To do. For this reason, in the power generation system 1 according to the present embodiment, as shown in FIG. 7, even when the operation load is increased from the minimum load to the rated load, the load is 300 MW as in the conventional power generation system. In this case, it increases continuously without becoming constant.

As described above, the boiler feedwater pump control device 40a and the APC control device 40b of the power generation system 1 according to the present embodiment set the load of the steam turbine 4 in advance in a state where the turbine-driven feedwater pump 25T1 is being driven. When the increased acceleration start load is reached, the turbine-driven feed water pump 25T2 is rotated to a rotation speed at which water can be supplied to the furnace 2, and the load is set to a preset in-service start load higher than the acceleration start load. When it reaches, water supply to the furnace 2 using the turbine drive type water supply pump 25T2 is started.
For this reason, the electric power generation system 1 can increase continuously between shortest load and rated load in a short time.

Next, in the power generation system 1 according to the present embodiment, a case where any one of the turbine-driven feed water pumps 25T1 and 25T2 is out-service while the turbine-driven feed water pumps 25T1 and 25T2 are being driven will be described.
FIG. 8 is a functional block diagram showing a flow of processing for switching control in the boiler feed pump control device 40a and the APC control device 40b for out-serving the turbine-driven feed water pump T2.

  As shown in FIG. 8, the APC control device 40b includes an output target value input unit 70, an output command value input unit 71, a BFP interlocking value input unit 72, a BFP out service selection input unit 73, and a condition determination unit 74. ing.

The command values input to the output target value input unit 70 and the output command value input unit 71 are compared with the set values input to the comparison units 75A and 75B, respectively.
For example, 185 MW is input as a setting value to the comparison unit 75A. When the target value input to the output target value input unit 70 is less than the set value, the comparison unit 75A outputs an ON signal to the AND gate 76, while the target value input to the output target value input unit 70 Is equal to or greater than the set value, an OFF signal is output to the AND gate 76.
For example, 245 MW is input as a setting value to the comparison unit 75B. When the command value input to the output command value input unit 71 is less than the set value, the comparison unit 75B outputs an ON signal to the AND gate 76, while the command value input to the output command value input unit 71. Is equal to or greater than the set value, an OFF signal is output to the AND gate 76.

Further, the BFP interlocking value input unit 72 outputs an ON signal to the AND gate 76 when the turbine-driven feed water pump 25T2 is in an in-service state.
Further, the BFP out service selection input unit 73 receives input of information indicating the turbine-driven feed water pump to be out of service. When the information is input, the BFP out service selection input unit 73 outputs an ON signal to the AND gate 76. In this embodiment, the case where the turbine-driven feed water pump 25T2 is out-of-service will be described. However, the turbine-driven feed water pump to be out-service is determined in advance according to the total operation time of the turbine-driven feed water pumps 25T1 and 25T2. ing.

The condition determining unit 74 determines whether or not the power generation system 1 satisfies various predetermined conditions for causing the turbine-driven feed water pump 25T2 to be out-service, and determines that the various conditions are satisfied. In this case, an ON signal is output to the AND gate 76, while an OFF signal is output to the AND gate 76 when it is determined that various conditions are not satisfied.
The various conditions include, for example, conditions that each recirculation valve 39 is not in the manual control mode and that the unit operation mode is in the cooperative control mode.

The AND gate 76 outputs an ON signal to the out service command output unit 77 when all the input signals are ON signals. When the ON signal output from the AND gate 76 is input, the out-service command output unit 77 outputs the ON signal to the notification processing unit 56 (for example, after 10 seconds), and then the selected turbine-driven water supply The out service command value is output to the pump 25T2.
When the ON signal is input, the notification processing unit 56 notifies the operator by voice that the turbine-driven water supply pump 25T2 starts out-service from the speaker provided in the operation unit 57. The notification processing unit 56 may display an image indicating that the turbine-driven feed water pump 25T2 starts out-service on the monitor of the operation unit 57.

  On the other hand, when the out-service command value is input from the out-service command output unit 77, the turbine-driven feed water pump 25T2 reduces and stops the water supply to the furnace 2. That is, in the power generation system 1 according to the present embodiment, when the load of the steam turbine 4 becomes less than 245 MW, the out-service of the turbine-driven feed water pump 25T2 is started. In the following description, a load for starting out-service, that is, a set value input to the comparison unit 75B is referred to as an out-service start load.

FIG. 9 is a functional block diagram showing a flow of processing of switching control in the boiler feed pump control device 40a for lowering the speed of the out-service turbine-driven feed water pump T2.
As shown in FIG. 9, the boiler feed pump control device 40 a includes an output target value input unit 80, a generator total power input unit 81, an out service completion signal input unit 82, and a condition determination unit 83.

The total values input to the output target value input unit 80 and the generator total power input unit 81 are compared with the set values input to the comparison units 84A and 84B, respectively.
For example, 155 MW is input as a setting value to the comparison unit 84A. Then, the comparison unit 84A outputs an ON signal to the AND gate 85 when the target value input to the output target value input unit 80 is less than the set value, while the target value input to the output target value input unit 80 Is equal to or greater than the set value, an OFF signal is output to the AND gate 85.
For example, 179 MW is input as a setting value to the comparison unit 84B. When the total value input to the generator total power input unit 81 is less than the set value, the comparison unit 84B outputs an ON signal to the AND gate 85 while being input to the generator total power input unit 81. When the total value is greater than or equal to the set value, an OFF signal is output to the AND gate 85.

  The out service completion signal input unit 82 outputs an ON signal to the AND gate 85 when the signal indicating that the out service has been completed is input from the turbine-driven feed water pump 25T2, while the above signal is input. If not, an off signal is output to the AND gate 85.

The condition determination unit 83 determines whether or not the power generation system 1 satisfies various predetermined conditions for lowering the turbine-driven feed water pump 25T2, and determines that the various conditions are satisfied. In this case, an ON signal is output to the AND gate 85, while an OFF signal is output to the AND gate 85 when it is determined that various conditions are not satisfied.
The various conditions are, for example, conditions that the in-service of the turbine-driven feed water pump 25T1 that is executing the remaining feed water amount control is completed.

The AND gate 85 outputs an ON signal to the deceleration command output unit 86 when all the input signals are ON signals. When the ON signal output from the AND gate 85 is input, the descending speed command output unit 86 outputs the ON signal to the notification processing unit 56 (for example, after 10 seconds), and then drops it to the turbine-driven feed water pump 25T2. The speed command value is output.
When the ON signal is input, the notification processing unit 56 notifies the operator by voice that the turbine-driven feed water pump 25T2 starts to descend from a speaker provided in the operation unit 57. Note that the notification processing unit 56 may cause the monitor of the operation unit 57 to display an image indicating that the turbine-driven feed water pump 25T2 starts to descend.

On the other hand, when the speed-decreasing command value is input from the speed-decreasing command output unit 86, the turbine-driven feed water pump 25T2 starts to descend. That is, in the power generation system 1 according to this embodiment, when the load of the steam turbine 4 becomes less than 179 MW, the turbine-driven feedwater pump 25T2 starts to descend.
Note that the setting value input to the comparison units 84A and 84B is set lower than the out-service start load.

  As described above, the boiler feedwater pump control device 40a and the APC control device 40b of the power generation system 1 according to this embodiment are configured to supply steam to the furnace 2 using the turbine-driven feedwater pumps 25T1 and 25T2. When the load on the turbine 4 is reduced to a preset out-service start load, the water supply to the furnace 2 by the turbine-driven feed water pump 25T2 is stopped, and the load on the steam turbine 4 is set in advance lower than the out-service start load. When the reduced speed start load is reached, the rotation of the turbine-driven feed water pump 25T2 is reduced.

  As shown in FIG. 10, in the power generation system 1 according to the present embodiment, even when the load is reduced from the rated load to the minimum load, the load can be continuously reduced in a short time.

  As mentioned above, although this invention was demonstrated using the said embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various changes or improvements can be added to the above-described embodiment without departing from the gist of the invention, and embodiments to which the changes or improvements are added are also included in the technical scope of the present invention.

  For example, in the above-described embodiment, the steam turbine 37 for driving the boiler feed pump for driving the turbine-driven feed water pumps 25T1 and 25T2 is extracted from the steam exhausted from the second superheater 7b and the low and medium pressure steam turbine 4b. However, the present invention is not limited to this, and the steam turbine 37 for driving the boiler feedwater pump includes the first superheater 7a, the second superheater 7b, and the high-pressure steam turbine. It is good also as a form with which steam is supplied from at least one of 4a and the low intermediate pressure steam turbine 4b.

  Moreover, although the said embodiment demonstrated the form provided with two turbine drive type water supply pumps and one electric drive type water supply pump as the boiler water supply pump 25, this invention is not limited to this, As boiler feed pump 25, it is good also as a form provided with three or more turbine drive type feed pumps and two or more electric drive type feed pumps.

  Moreover, although the steam turbine 4 demonstrated the form provided with the high pressure steam turbine 4a and the low and medium pressure steam turbine 4b in the said embodiment, this invention is not limited to this, The steam turbine 4 is one steam. It is good also as a form provided with three turbines, the form provided with a turbine, and the steam turbine 4 of a high pressure steam turbine, a medium pressure steam turbine, and a low pressure steam turbine.

  Moreover, although the form which the furnace 2 burns liquid fuel was demonstrated in the said embodiment, this invention is not limited to this, The furnace 2 is good also as a form which burns solid fuels, such as coal.

DESCRIPTION OF SYMBOLS 1 Power generation system 2 Furnace 7 Superheater 11 1st steam piping 12 2nd steam piping 13 3rd steam piping 15 Boiler throttle valve 16 Boiler throttle bypass valve 17 Turbine governor 24 Deaerator 25 Boiler feed pump 40a Boiler feed pump control apparatus 40b APC controller

Claims (7)

A power generation system control device comprising: a furnace that combusts fuel and generates steam by heat of combustion; a steam turbine that rotates by steam generated by the furnace; and a plurality of feed water pumps that supply water to the furnace There,
In a state where water is supplied to the furnace using a predetermined water pump among the plurality of water pumps, an output target value of the steam turbine exceeds a preset first set value, and the steam When the load on the turbine reaches a preset first value, the other feed water pump is rotated to a rotational speed at which water can be supplied to the furnace, and the output target value is a preset second set value. And when the load reaches a preset second value higher than the first value, the first control is performed to start the water supply to the furnace using the other water supply pump. Control device for power generation system.   In the state where water is supplied to the furnace using a plurality of the water pumps, when the load is reduced to a preset third value, water is supplied to the furnace by the preset water pump. 2. The power generation according to claim 1, wherein when the load reaches a preset fourth value lower than the third value, the second control is performed to reduce the rotation of the feed pump. System control unit. The power generation system includes:
A deaerator for degassing water supplied to the water supply pump;
A pipe that is provided for each of the feed water pumps and that feeds the feed water fed from the feed water pump to the deaerator;
A valve that is provided for each pipe and is opened when the amount of water supplied by the water supply pump is larger than the load; and
With
The power generation system control device according to claim 1 or 2, wherein the valve is closed when the first control is performed.   In the other water supply pump, the bearing oil temperature of the rotating shaft before the first control is performed is the first control, and the load of the steam turbine is changed from the first value to the second value. The control device for a power generation system according to any one of claims 1 to 3, wherein the control device is set so as to reach a predetermined temperature at which the water can be supplied to the furnace. A furnace for burning fuel and generating steam by the heat of the combustion;
A steam turbine that generates electricity by rotating the turbine using steam generated by the furnace;
A plurality of water supply pumps for supplying water to the furnace;
A control device according to any one of claims 1 to 4,
Power generation system with A superheater that is provided between the furnace and the steam turbine and superheats steam;
A first steam pipe connecting the furnace and the superheater;
A second steam pipe connecting the superheater and the steam turbine;
A first valve provided in the first steam pipe;
A turbine governor provided in the second steam pipe;
Control means for adjusting the opening of the first valve in accordance with the load of the steam turbine;
The power generation system according to claim 5, further comprising: A power generation system control method comprising: a furnace that burns fuel and generates steam by the heat of combustion; a steam turbine that rotates by steam generated by the furnace; and a plurality of feed water pumps that supply water to the furnace There,
In a state where water is supplied to the furnace using a predetermined water pump among the plurality of water pumps, an output target value of the steam turbine exceeds a preset first set value, and the steam When the load on the turbine reaches a preset first value , the other feed water pump is rotated to a rotational speed at which water can be supplied to the furnace, and the output target value is a preset second set value. And when the load reaches a preset second value that is higher than the first value , the method of controlling the power generation system starts water supply to the furnace using the other water supply pump. .

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