WO2020255719A1

WO2020255719A1 - Power plant

Info

Publication number: WO2020255719A1
Application number: PCT/JP2020/021961
Authority: WO
Inventors: 山本　健次郎; ▲祥▼三金子; 裕二行木; 俊一那須; 佐々木　健次; 大二郎平崎; 小阪　健一郎; 眞二中村; 瞭介菅; 優太小林
Original assignee: 三菱パワー株式会社
Priority date: 2019-06-19
Filing date: 2020-06-03
Publication date: 2020-12-24
Also published as: JP7291010B2; JP2021001551A

Abstract

According to the present invention, an FCB operation is efficiently performed, and a subsequent in-house single load operation is also smoothly performed. This power plant comprises: a boiler (110); steam turbines (121, 122, 123); a water supply line (130) that supplies exhaust steam from the steam turbines to the boiler via a steam condenser (131) that returns the exhaust steam to water; a makeup water line (221) that supplies makeup water onto a flow path through which heated steam generated by the boiler returns to the boiler via a water supply line and a makeup water opening/closing valve (231) that opens and closes the makeup water line; and a control device (150) that controls the opening degrees of a pressure control valve and the makeup water opening/closing valve (231), wherein in an initial step from the start of a fast cutback operation performed when the power plant is shut off from the power plant to an in-house single load operation that generates in-house auxiliary power of the power plant in a state in which the power plant is shut off from the power transmission system, the pressure control valve and the makeup water opening/closing valve are controlled to an open state.

Description

Power plant

The present invention relates to a power plant, and particularly to a fast cutback technology in a steam power plant that utilizes the heat of combustion of various fuels.

According to Patent Document 1, when a load cutoff is detected, the steam control valve provided between the boiler and the high-pressure steam turbine and the intercept valve provided between the high-pressure steam turbine and the low-pressure steam turbine are suddenly closed. The protection circuit of the above, the second protection circuit that suddenly closes the intercept valve and suddenly opens the low-pressure steam turbine bypass valve, the phase difference angle detection device of the generator, and the phase difference angle detected by the phase difference angle detection device are on the deceleration side. Disclosed is a steam turbine provided with a step-out prevention device that suddenly opens the intercept valve until the predetermined set opening or phase difference angle reverses to the speed-increasing side and rapidly closes the low-pressure steam turbine bypass valve. There is.

Further, Patent Document 2 is provided with a steam control valve and an emergency release valve that is always closed in the main steam pipe through which steam generated in the boiler flows, and is fully opened in response to an open signal from the control unit to release the steam generated in the boiler. The function of promptly discharging from the main steam pipe to the outside is disclosed.

Japanese Unexamined Patent Publication No. 5-65805 Japanese Unexamined Patent Publication No. 2003-148111

In the event of an accident in the transmission line system, etc., the generator is disconnected from the system, and the generated power is reduced to a few percent of the in-house auxiliary power during normal operation, so-called Fast Cut Back (FCB). ) Driving is done. When shifting to this FCB operation, the steam turbine that drives the generator becomes a single load state in the facility. Then, the input of water supply to the boiler is rapidly narrowed down to the minimum load, and the operation shifts to the in-house single load operation.

However, the boiler has a time lag before it is narrowed down to the minimum load. That is, the amount of steam generated from the boiler cannot be instantly narrowed down to the amount required for the in-house single load operation immediately after the FCB operation, and during that time, surplus steam is generated based on the in-house single load operation level.

In Patent Document 1, since this excess steam flows from the high-pressure steam turbine bypass provided between the boiler and the steam control valve to the condenser, it is relatively easy to perform FCB operation smoothly and responsively. A large condenser is required.

Therefore, as a measure to avoid increasing the size of the condenser, it is conceivable to release the main steam discharged from the superheater to the atmosphere, for example, as in Patent Document 2.

However, since a certain amount of water is circulated in the steam circulation system from the boiler to the turbine, when it is opened to the atmosphere, it is necessary to operate with the amount of water equivalent to the open to the atmosphere reduced during single load operation in the facility. A new problem arises. Therefore, a smooth transition from the start of FCB operation to the in-house single load operation cannot be achieved by simply combining Patent Document 1 with Patent Document 2.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique for efficiently performing FCB operation and smoothly performing subsequent in-house single load operation.

In order to achieve the above object, in the present invention, in a power plant, a boiler that heats supplied water to generate superheated steam and steam that is rotationally driven by the superheated steam heated by the boiler to drive a generator. A water supply line that supplies the boiler to the boiler via a turbine and a water recovery device that returns the exhaust steam from the steam turbine to water, and superheated steam generated by the boiler returns to the boiler via the water supply line. On the flow path, a pressure control valve for releasing the superheated steam to the atmosphere, a make-up water line for supplying make-up water to the flow path through which the superheated steam generated by the boiler returns to the boiler via the water supply line, and a make-up water line. A make-up water on-off valve that opens and closes the make-up water line, and a control device that controls the opening and closing of the pressure control valve and the make-up water on-off valve are provided, and the control device connects the power generation plant to a power transmission system. During normal operation, the pressure control valve and the make-up water on-off valve are controlled to be closed, and the fast cutback operation performed when the power plant is shut off from the transmission system is started from the transmission system. It is characterized in that the pressure control valve and the make-up water on-off valve are controlled to be in an open state in the initial stage up to the in-house single load operation in which the in-house auxiliary power of the power plant is generated in a shut-off state.

According to the present invention, FCB operation can be efficiently performed, and subsequent in-house single load operation can be smoothly performed. Issues, configurations and effects other than those described above will be clarified by the description of the following embodiments.

Fluid system diagram of the power plant of this embodiment Configuration diagram of control device Flowchart showing the operation flow of a power plant The figure which shows the opening degree of each control valve in normal operation, FCB operation, and in-house single load operation The figure which shows the opening degree of each spray valve in normal operation, FCB operation, and in-house single load operation System configuration diagram of power plant during normal operation System configuration diagram of power plant in the first half of the initial stage of FCB operation System configuration diagram of power plant in the latter half of the initial stage of FCB operation System configuration diagram of the power plant during single load operation in the facility

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same components and processes are designated by the same reference numerals, and duplicate description will be omitted.

FIG. 1 is a fluid system diagram of the power plant 100 of the present embodiment. The power generation plant 100 has a boiler 110 that burns fuel and generates steam by the heat of the combustion, and a steam turbine that drives a generator 101 by rotating a turbine using the steam generated by the boiler 110 to generate power. Specifically, a high-pressure steam turbine (HPT) 121, a medium-pressure steam turbine (IPT) 122, a low-pressure steam turbine (LPT) 123, a water supply line 130 for supplying water to the boiler 110, and a control device 150 (FIG. 2). ) And.

The boiler 110 includes an economizer (ECO) 111, a fireplace water cooling wall 112, a brackish water separator 113, a superheater 114, and a reheater 115. The superheater 114 may be provided in a plurality of stages from the downstream to the upstream. The reheater 115 may also be provided in a plurality of stages from the downstream to the upstream.

On the water supply line 130, there are a condenser 131, a condenser pump 132, a low pressure water supply superheater (low pressure heater) 133, a deaerator 134, a water supply pump 135, and a high pressure water supply superheater (high pressure heater) 136. And are provided.

A make-up water line 221 that supplies make-up water to the water supply line 130 is connected to the condenser 131. Further, the make-up water line 221 is provided with a make-up water on-off valve 231 for switching between supply / stop of make-up water.

In the power plant 100 having the above configuration, the economizer 111 preheats the supplied water by heat exchange with the combustion gas. The water preheated by the economizer 111 produces a water-steam two-phase fluid in the furnace water cooling wall 112 by passing through a furnace wall pipe (not shown) formed on the wall. The water-steam two-phase fluid generated in the furnace water cooling wall 112 is sent to the brackish water separator 113 and separated into saturated steam and saturated water. Here, the saturated steam is guided to the superheater 114, and the saturated water is guided to the condenser 131 through the first pipe 161.

The saturated steam separated by the steam water separator 113 is superheated by the superheater 114 by heat exchange with the combustion gas, and is supplied to the high-pressure steam turbine 121 via the main steam pipe 162. The outlet of the high pressure steam turbine 121 is connected to the low temperature reheat steam pipe 163. The low temperature reheat steam pipe 163 is connected to the reheater 115. The low temperature reheat steam pipe 163 is branched and connected to the ventilator line 199 at the first connection point 191 in front of the reheater 115. The ventilator line 199 is connected to the condenser 131.

In the low temperature reheat steam pipe 163, an exhaust forced check valve 192 for suppressing the backflow of steam to the high pressure steam turbine 121 is provided between the first connection point 191 and the reheater 115.

In the ventilator line 199, a ventilator valve 193 is provided between the first connection point 191 and the condenser 131. The ventilator valve 193 is in a constantly closed state, and is fully opened during FCB operation, and fully closed during normal operation and in-house single load operation.

The steam that has performed the predetermined work in the high-pressure steam turbine 121 is guided to the reheater 115 via the low-temperature reheat steam pipe 163 during normal operation. The normal operation here means an operation in a state of being connected to a power transmission system.

In the reheater 115, the steam that has performed the predetermined work in the high-pressure steam turbine 121 is reheated. The steam superheated by the reheater 115 is supplied to the medium-pressure steam turbine 122 and the low-pressure steam turbine 123 via the high-temperature reheat steam pipe 164, where they perform work and drive the generator 101. The main steam pipe 162 is provided with a first shutoff valve 176 that is always open.

The high temperature reheat steam pipe 164 is provided with a pressure control valve 197 that is always closed and a second shutoff valve 177 that is always open along the order from the reheater 115 to the medium pressure steam turbine 122.

A second connection point 194 between the superheater 114 and the first shutoff valve 176 in the main steam pipe 162 and a third connection point 195 on the downstream side of the exhaust forced check valve 192 in the low temperature reheat steam pipe 163. Is connected by a first high-pressure bypass steam pipe 165. The first high-pressure bypass steam pipe 165 is provided with a first bypass on-off valve 171 that is always closed.

Further, in the main steam pipe 162, the fourth connecting point 196 between the superheater 114 and the second connecting point 194 and the condenser 131 are connected by the second high-pressure bypass steam pipe 167. The second high-pressure bypass steam pipe 167 is provided with a second bypass on-off valve 172 that is always closed.

The steam that has finished its work in the low-pressure steam turbine 123 is supplied to the condenser 131 by the first exhaust steam pipe 166. The condensate condensed by the condenser 131 is sent to the deaerator 134 after passing through the low pressure heater 133 by the condensate pump 132 together with the saturated water sent from the brackish water separator 113, and the gas component in the condensate is removed. Will be done. The condensate that has passed through the deaerator 134 is further boosted by the water supply pump 135, then fed to the high-pressure heater 136 to be heated, and finally returned to the boiler 110.

In addition, the power generation facility 100 is provided with four sprays for controlling the temperature of superheated steam. Specifically, the flow path in the superheater 114 having a plurality of stages is provided with a first water supply port 201 into which the water supply from the preheater spray 211 flows in. The front superheater water supply line 215, which serves as a flow path for water supply from the front superheater spray 211 to the first water supply port 201, is provided with a front superheater spray valve 202.

The outlet of the superheater 114 is provided with a second water supply port 203 into which the spray from the subsequent superheater spray 212 flows in. A rear-stage superheater spray valve 204 is provided in the rear-stage superheater water supply line 216, which is a flow path for water supply from the rear-stage superheater spray 212 to the second water supply port 203.

The flow path in the reheater 115 composed of a plurality of stages is provided with a third water supply port 205 into which the spray flows from the previous stage reheater spray 213. The preheater spray valve 206 is provided in the preheater water supply line 217, which is a flow path for water supply from the preheater spray 213 to the third water supply port 205.

The outlet of the reheater 115 is provided with a fourth water supply port 207 into which the spray from the subsequent reheater spray 214 flows in. The rear reheater water supply line 218, which is the flow path for the spray from the rear reheater spray 214 to the fourth water supply port 207, is provided with the rear reheater spray valve 208. In FIG. 1, for convenience of explanation, the signal line connecting the control device 150 (see FIG. 2) and each control valve is shown in a simplified manner, but each control valve and the control device 150 are connected to each other via a signal line. Connected electrically or by communication. Then, the opening degree control signal of the control device 150 is transmitted to each control valve, and the opening / closing control of each control valve is executed.

FIG. 2 is a configuration diagram of the control device 150.

As shown in FIG. 2, the control device 150 includes a CPU (Central Processing Unit) 301, a RAM (Random Access Memory) 302, a ROM (Read Only Memory) 303, an HDD (Hard Disk Drive) 304, an input I / F 305, and an input I / F 305. Includes outputs I / F 306, which are configured using computers connected to each other via bus 307.

The hardware configuration of the control device 150 is not limited to the above, and may be configured by a combination of a control circuit and a storage device. Further, the control device 150 is configured by executing an operation program by a computer (hardware). The control device 150 controls the opening and closing of each control valve according to an instruction from the outside (a control console or the like placed in the power plant) or signals from various sensors installed in the power plant 100.

The power plant 100 shifts from system 1 (see FIG. 4) to system 2 (see FIG. 4) described below during FCB operation. System 1 is a system used in the stage from immediately after the start of FCB operation to the in-house single load operation (initial stage of opening to the atmosphere). System 2 is a system used for in-house single load operation. It is conceivable that the steam temperature rises during FCB operation in any of the systems, but the effect of the system 1 is relatively smaller than that of the system 2. Therefore, since it is easy to make FCB successful from the viewpoint of controllability such as steam temperature, FCB operation is first performed using system 1.

In system 1, FCB operation is performed by opening to the atmosphere. As a result, the load drops at once, the amount of work in the steam turbine is reduced, and the heat drop is reduced, so that the steam temperature rises. As a result, the steam temperature (measured values of the temperature sensors T1 and T2) exceeds the set temperature. Therefore, a spray is blown to lower the steam temperature. The temperature sensor T1 measures the outlet temperature of the superheater 114, that is, the main steam temperature. The temperature sensor T2 measures the outlet temperature of the reheater 115, that is, the reheated steam temperature.

Furthermore, in system 1, the circulating water is reduced by the amount released to the atmosphere. Therefore, the make-up water on-off valve 231 is switched from the closed state to the open state, and water is supplied from the make-up water line 221 to the condenser 131. However, since the amount that can be replenished is limited, it is desirable to stop the release to the atmosphere as soon as possible, that is, to close the pressure control valve 197.

Next, the power plant 100 shifts to system 2 and continues the in-house single load operation. By shifting to the system 2, the opening to the atmosphere is completed and the pressure control valve 107 is closed. In addition, with the end of opening to the atmosphere, water supply will no longer be required. Therefore, the make-up water on-off valve 231 switches from the open state to the closed state. On the other hand, in the system 2, since the flow rate of steam passing through the reheater 115 is reduced as compared with the case of the system 1, the reheated steam temperature tends to rise. Therefore, since it is necessary to blow the spray further, the front stage spray is almost fully opened on both the superheater 114 side and the reheater 115 side. Since it may not be possible to deal with this alone, a subsequent spray will be added and used as appropriate. The details will be described below.

FIG. 3 is a flowchart showing the operation flow of the power plant 100.

The power plant 100 supplies steam to the high-pressure steam turbine 121, the medium-pressure steam turbine 122, and the low-pressure steam turbine 123 in a state of being connected to the power transmission system, and performs a normal operation to drive the generator 101 (S1). .. When the control device 150 receives a system cutoff signal indicating that the power transmission system has been cut off during normal operation (S2: Yes), the power plant 100 shifts to FCB operation to be performed in the case of a system accident (S3). .. If the system cutoff signal is not received (S2: No), the normal operation is continued (S1).

FCB operation will be continued until the conditions for transition to single load operation in the facility are satisfied (S4: No). During FCB operation, if the operation performed to maintain the function of the power plant 100 while shut off from the power transmission system, that is, the transition condition to the so-called in-house single load operation is satisfied (S4: Yes), the in-house single load operation is started. (S5).

Until the conditions for returning to the power transmission system are satisfied (S6: No), the in-house single load operation will be continued. When the condition for returning to the power transmission system is satisfied during the single load operation in the facility (S6: Yes), the operation for returning to the power transmission system is performed and the normal operation is restored (S1).

FIG. 4 is a diagram showing the opening degree of each control valve in normal operation, FCB operation, and in-house single load operation. FIG. 5 is a diagram showing the opening degree of each spray valve in normal operation, FCB operation, and in-house single load operation. FIG. 6 is a system configuration diagram of the power plant 100 during normal operation.

During normal operation, as shown in FIGS. 4 and 6, the pressure control valve 197, the make-up water on-off valve 231 and the first bypass on-off valve 171, the second bypass on-off valve 172, and the ventilator valve 193 are all in the closed state. Further, during normal operation, since the steam temperature is controlled by using the front stage superheater spray 211, the front stage superheater spray valve 202 is in the open state (opening less than 100%) and the rear stage superheater, as shown in FIGS. 4 and 5. The instrument spray valve 204, the front stage reheater spray valve 206, and the rear stage reheater spray valve 208 are in the closed state.

In the system configuration of the normal operation shown in FIG. 6, the spray is sprayed from the superheater spray 211 in the previous stage to the flow path in the superheater 114 via the first water supply port 201. The main steam flowing into the main steam pipe 162 discharged from the superheater 114 is because the first shutoff valve 176 is always open and the first bypass on-off valve 171 and the second bypass on-off valve 172 are always closed. , It is supplied to the high pressure steam turbine 121 through the first shutoff valve 176 without passing through the first high pressure bypass steam pipe 165 and the second high pressure bypass steam pipe 167.

On the other hand, since the ventilator valve 193 is always closed, the discharged steam discharged from the high-pressure steam turbine 121 is supplied from the low-temperature reheat steam pipe 163 to the reheater 115.

During normal operation, the pressure control valve 197 is closed and the second shutoff valve 177 is open, so that the total amount of reheated steam reheated by the reheater 115 is from the high temperature reheated steam pipe 164 to the medium pressure steam turbine. It is supplied in the order of 122 and the low pressure steam turbine 123. Further, since the make-up water on-off valve 231 is closed, the supply of make-up water is stopped.

The exhaust steam discharged from the low-pressure steam turbine 123 is supplied from the first exhaust steam pipe 166 to the condenser 131. After that, it returns to the boiler 110 via the water supply line 130.

FIG. 7 is a system configuration diagram of the power plant 100 in the first half of the initial stage of FCB operation. FIG. 8 is a system configuration diagram of the power plant 100 in the latter half of the initial stage of FCB operation.

After the start of FCB operation, excess steam is released to the atmosphere from the pressure control valve 197. At that time, first of all, in order to suppress the further generation of excess steam, the spray spraying by each sprayer is stopped. On the other hand, in order to keep the flow rate in the system constant, it is necessary to supply water as much as the steam is released to the atmosphere. Therefore, after starting the opening of the excess steam to the atmosphere, the pressure control valve 197 is opened to continue the opening to the atmosphere, and the make-up water on-off valve 231 is also opened to start the supply of make-up water.

Specifically, during FCB operation, the pressure control valve 197, the make-up water on-off valve 231 and the first bypass on-off valve 171 and the ventilator valve 193 are in the open state, as shown in FIGS. 4 and 7. Further, the second bypass on-off valve 172 is in a closed state immediately after the FCB operation and then in an open state. Further, during FCB operation, as shown in FIGS. 5 and 7, all spray valves are closed (see FIG. 7). Then, when the steam temperature measured by the temperature sensors T1 or T2 exceeds the set temperature after a certain period of time has passed after the FCB operation, the preheater spray valve 206 of the previous stage is first opened (opening less than 100%), and after a while. The preheater spray valve 202 is fully opened (see FIG. 8). The post-stage superheater spray valve 204 and the post-stage reheater spray valve 208 operate in an auxiliary operation, for example, during a sudden temperature change.

In the FCB operation system configuration shown in FIG. 7, the main steam flowing into the main steam pipe 162 discharged from the superheater 114 goes to the first high-pressure bypass steam pipe 165 and the high-pressure steam turbine 121 at the second connection point 194. Branch. Therefore, the amount of main steam supplied to the high-pressure steam turbine 121 can be reduced as compared with the normal operation.

The main steam branched to the first high-pressure bypass steam pipe 165 and the exhaust steam from the high-pressure steam turbine 121 are supplied to the reheater 115 via the low-temperature reheat steam pipe 163.

The reheated steam discharged from the reheater 115 flows through the high-temperature reheated steam pipe 164, and a part of it is released to the atmosphere from the pressure control valve 197. As a result, excess steam during FCB operation is released to the outside of the steam circulation system.

The reheated steam that has not been released to the atmosphere is supplied to the condenser 131 via the high-temperature reheated steam pipe 164 via the medium-pressure steam turbine 122 and the low-pressure steam turbine 123. Since the make-up water on-off valve 231 is in the open state, make-up water is supplied near the condenser 131. As a result, water corresponding to the reduced amount of steam as a result of being released to the atmosphere can be supplied to the steam circulation system of the power plant 100. Then, the make-up water and the water from the condenser 131 are returned to the boiler 110 via the water supply line 130.

The control device 150 acquires the measured values from the temperature sensors T1 and T2, and when it is determined that the steam temperature is equal to or higher than the set temperature, controls the preheater spray valve 206 in the open state. Subsequently, the front stage superheater spray valve 202 is controlled to be in the open state (see FIG. 8).

FIG. 9 is a system configuration diagram of the power plant 100 during single load operation in the facility.

Since the system shown in Fig. 9 does not open to the atmosphere, there is no need to replenish water for the open to the atmosphere. Therefore, as shown in FIGS. 4 and 9, the pressure control valve 197 and the make-up water on-off valve 231 are in the closed state during the in-house single load operation. Further, the first bypass on-off valve 171 and the ventilator valve 193 are also in the closed state. Further, the second bypass on-off valve 172 is in the open state. Further, during single load operation in the facility, as shown in FIGS. 5 and 9, the front stage superheater spray valve 202 and the front stage reheater spray valve 206 are in the open state, the rear stage superheater spray valve 204 is closed, and the rear stage reheater spray is closed. The valve 208 is an auxiliary operation, that is, it opens or closes according to the steam temperature measured by the temperature sensors T1 and T2 (see FIG. 4).

In the system configuration of the in-house single load operation shown in FIG. 9, the water supply to the steam circulation system of the power plant 100 is stopped, that is, the make-up water on-off valve 231 is controlled to be closed. The main steam flowing into the main steam pipe 162 discharged from the superheater 114 is the first because the first shutoff valve 176 is open, the first bypass on-off valve 171 is closed, and the second bypass on-off valve 172 is open. At the four connection points 196, a part of the main steam passes through the second high-pressure bypass steam pipe 167 and the rest passes through the first shutoff valve 176 and is supplied to the high-pressure steam turbine 121. Therefore, the amount of main steam supplied to the high-pressure steam turbine 121 is smaller in the in-house single load operation than in the normal operation. The exhaust steam of the high-pressure steam turbine 121 is supplied to the reheater 115 via the low-temperature reheat steam pipe 163.

On the other hand, since the ventilator valve 193 is closed, the discharged steam discharged from the high-pressure steam turbine 121 is supplied from the low-temperature reheat steam pipe 163 to the reheater 115.

Further, the main steam branched from the fourth connection point 196 to the second high-pressure bypass steam pipe 167 is supplied to the condenser 131. After that, it returns to the boiler 110 via the water supply line 130.

Generally, in the power generation plant 100, when an accident occurs in the transmission line system or the like, the generator 101 is disconnected from the system, and the generated power is reduced to the in-house auxiliary power equivalent to several% of the normal operation, so-called fast cut. Back (Fast Cut Back (FCB)) operation is performed. When shifting to this FCB operation, the steam turbine that drives the generator 101 becomes a single load state in the facility. Therefore, the input of water supply or the like to the boiler 110 is rapidly narrowed down to the minimum load, and the operation is shifted to the in-house single load operation.

At that time, the power plant 100 according to the present embodiment restores the excess steam generated during FCB operation by releasing the excess steam from the pressure control valve 197 to the atmosphere, as compared with the case where the entire amount of the surplus steam is supplied to the condenser 131. The capacity of the condenser 131 can be reduced. Therefore, it is possible to avoid the enlargement of the condenser 131 and contribute to the realization of the miniaturization of the power plant 100.

Further, when the power plant 100 according to the present embodiment is opened to the atmosphere, the make-up water on-off valve 231 is opened to supply make-up water. This makes it possible to compensate for the loss of water from the steam circulation system caused by the opening to the atmosphere.

As a result, the amount of steam required during the in-house single load operation following the FCB operation can be supplemented, and a smooth transition to the in-house single load operation becomes possible.

The present invention is not limited to the above embodiments and modifications, and various modifications can be made according to the design and the like as long as the technical idea of the present invention is not deviated. For example, the adjustment of the amount of water supply such as water supply / stoppage of make-up water is realized by sending a control signal from the control device 150 to the make-up water on-off valve 231 in the above embodiment. However, the make-up water pump is provided in the make-up water line 221 instead of the make-up water on-off valve 231, and the rotation speed of the make-up water pump (rotation speed per unit time: rpm) is variably controlled by the control device 150 to make make-up water. The amount of make-up water discharged from the pump may be adjusted.

100: Power plant 101: Generator 110: Boiler 111: Coal saver 112: Fire furnace water cooling wall 113: Steam water separator 114: Superheater 115: Condenser 121: High pressure steam turbine 122: Medium pressure steam turbine 123: Low pressure steam Turbine 130: Water supply line 131: Condenser 132: Condensate pump 133: Low pressure heater 134: Deaerator 135: Water supply pump 136: High pressure heater 150: Control device 161: First pipe 162: Main steam pipe 163: Low temperature re-cooling Hot steam pipe 164: High temperature reheated steam pipe 165: First high pressure bypass steam pipe 166: First exhaust steam pipe 167: Second high pressure bypass steam pipe 171: First bypass on-off valve 172: Second bypass on-off valve 176: First 1 Block valve 177: 2nd block valve 191: 1st connection point 192: Exhaust forced check valve 193: Ventilator valve 194: 2nd connection point 195: 3rd connection point 196: 4th connection point 197: Pressure control Valve 199: Ventilator line 201: 1st water supply port 202: Front stage superheater spray valve 203: 2nd water supply port 204: Rear stage superheater spray valve 205: 3rd water supply port 206: Front stage condenser spray valve 207: 4th water supply port Mouth 208: Rear-stage condenser spray valve 211: Front-stage superheater spray 212: Rear-stage superheater spray 213: Front-stage reheater spray 214: Rear-stage condenser spray 215: Front-stage superheater water supply line 216: Rear-stage superheater water supply line 217 : Front stage condenser water supply line 218: Rear stage condenser water supply line 221: Makeup water line 231: Makeup water on-off valve 301: CPU
302: RAM
303: ROM
304: HDD
305: Input I / F
306: Output I / F
307: Bus

Claims

In a power plant
A boiler that heats the supplied water to generate superheated steam,
A steam turbine that is rotationally driven by superheated steam overheated in the boiler to drive a generator, and
A water supply line that supplies the exhaust steam from the steam turbine to the boiler via a condenser that returns the steam to water.
A pressure control valve for releasing the superheated steam to the atmosphere on a flow path through which the superheated steam generated by the boiler returns to the boiler via the water supply line.
A make-up water line that supplies make-up water on a flow path through which the superheated steam generated by the boiler returns to the boiler via the water supply line, a make-up water on-off valve that opens / closes the make-up water line, and a make-up water on-off valve.
A control device for controlling the opening degree of the pressure control valve and the make-up water on-off valve is provided.
The control device is
During normal operation in which the power plant is connected to the power transmission system and operated, the pressure control valve and the make-up water on-off valve are controlled to be closed.
In the initial stage from the start of the fast cutback operation performed when the power plant is cut off from the power transmission system to the in-house single load operation for generating the in-house auxiliary power of the power plant in the state of being cut off from the power transmission system. , Control the pressure control valve and the make-up water on-off valve in the open state.
A power plant characterized by that.
In the power plant according to claim 1.
The control device is
After the end of the initial stage of the fast cutback operation, the pressure control valve and the make-up water on-off valve are used during the in-house single load operation in which the in-house auxiliary power of the power plant is generated in a state of being cut off from the power transmission system. To be closed,
A power plant characterized by that.