JP5550020B2 - Water supply pump controller - Google Patents

Description

  The present invention relates to a feedwater pump control device for thermal power and nuclear power plants.

  Generally, in a nuclear power plant or a thermal power plant, a steam turbine is driven by steam generated by a steam generator such as a nuclear reactor or a boiler, and the steam after driving the steam turbine is cooled by a condenser to condensate. It is said. This condensate is pressurized and supplied to the steam generator by a water supply device including a condensate pump and a water supply pump each including a plurality of units including a spare machine.

  When one condensate pump on the upstream side of such a water supply device trips, the flow rate output from the condensate pump decreases, so when the water supply pump that is the downstream pump is normally operated, the upstream side Operation beyond the overflow range (hereinafter referred to as the runout region) where the remaining condensate pump is transiently recognized for a certain period of time due to the flow rate imbalance between the flow rate that the condensate pump can normally supply and the downstream feed water pump These condensate pumps may be damaged. Further, since the required suction pressure is not ensured in the water supply pump, cavitation occurs and there is a risk of damage.

Therefore, in such a case, it is necessary to take measures to balance the flow rate of the upstream pump and the downstream pump.
A water supply device having an inverter device for driving a water pump drive motor at a variable speed, and when the control device detects a trip of the operating condensate pump, all the water supply pump inverters in operation are connected to the inverter device. Executes a trip time control that outputs a deceleration operation command at the set speed, and then outputs a start command to the spare unit of the tripped condensate pump and outputs a return command to the normal state for all inverter devices of the feed pump There is one that performs the return time control (see, for example, Patent Document 1).

JP 2009-204255 A

  In Patent Document 1 described above, for example, when a normal plant water supply flow rate is supplemented by operating three condensate pumps and three water supply pumps, the water supply flow rate for each pump is 33% of the plant water supply flow rate. Become. Therefore, in the trip time control when one condensate pump trips, the inverter device of the feed water pump outputs a deceleration operation command for reducing the plant feed water flow rate from 100% to 66%. In the return control, the condensate pump preliminary machine start command is output, and after confirming the start of the spare machine, the inverter device of the feed water pump issues a speed increasing operation command to increase the plant water supply flow rate from 66% to 100%. Output.

However, the behavior of the water supply device during this condensate pump trip has the following problems.
(1) Due to the characteristics of the inverter device, the rotational speed of the water supply pump cannot be rapidly decreased. Therefore, even if the deceleration operation command is received, the rate of decrease in the actual rotation speed of the water supply pump is limited.
(2) The condensate pump, which is a spare machine, is normally started within a short time after the trip of one condensate pump, and the start of the spare machine is confirmed by a closing contact signal of the power breaker Therefore, the time during which the above-described deceleration operation command is output is short. After confirming the start-up of the spare machine, an acceleration operation command for returning to the normal flow rate is output.
(3) That is, the output time of the deceleration operation command for reducing the plant water supply flow rate from 100% to 66% is short, and even if the deceleration operation command is received, the inverter device cannot rapidly decrease the rotation speed of the water supply pump, And since the speed-up operation command which increases a plant water supply flow rate from 66% to 100% is output immediately afterward, the actual rotational speed of a water supply pump may be hardly decelerated.
(4) In this case, even if the condensate pump, which is a spare machine, is started, the flow rate can be secured several seconds later, but the two condensate pumps that did not trip are There is a problem of continuing the driving of.
(5) Even if the rotation speed of the feed water pump driven by the inverter device can be sufficiently reduced, the speed increase of the feed water pump can only be increased gradually due to the characteristics of the inverter device. It takes a certain time to reach the rotation speed corresponding to the plant feed water flow rate. For this reason, there exists a problem that the water level of a steam generator falls large in the meantime.
(6) Furthermore, since there is no description of the control when the spare condensate pump is not started, there is a problem that, for example, when deceleration control is continued, the steam generator shifts to a plant trip due to a drop in the water level.

  The present invention has been made based on the above-mentioned matters, and its purpose is to reduce the amount of decrease in the feed water flow rate to the steam generator when the condensate pump trips, and to suppress the amount of decrease in the water level of the steam generator, An object of the present invention is to provide a feed water pump control device that prevents continuation of run-out operation of a condensate pump that continues operation.

In order to achieve the above object, the first invention provides a condensate pump in which a plurality of units are installed in parallel to boost the condensate from the condenser, and the condensate boosted by the condensate pump. The water supply device further comprises a water supply pump having a plurality of water supply pumps installed in parallel for boosting and supplying to the steam generator, and a variable frequency power supply device for driving the motor of the water supply pump at a variable speed, A feedwater pump control device that controls the rotational speed of the feedwater pump by outputting a frequency control command to a variable frequency power supply device, wherein the feedwater pump control device detects a trip of the condensate pump during operation. A trip time control means for changing a maximum flow rate limit value for a frequency control command to the variable frequency power supply device to a runout flow rate that allows a short-time operation only during a transient, and the condensate pump When detecting the spare machine startup, the return time control means for changing the maximum flow rate limit value to the normal flow rate from the run-out rate, when detecting the pre-press non activation of the condensate pump, the maximum flow rate limit value from the run-out flow rate It is assumed that control means for changing the normal operation flow rate of the number of the condensate pumps that have been operated is provided.

According to a second aspect of the present invention, in the first aspect of the invention, when the feedwater pump control device detects that the condensate pump is not activated, a command for requesting a reduction in the output of the steam generator is issued to the steam generator. And a control means for outputting to the output control device .

Further, in a third aspect based on the second aspect , when the feed pump control device detects that the spare pump of the condensate pump has not been started, the same number as the number of condensate pumps that have been operated continues. Control means for changing the number of operating water pumps is provided .

  According to the present invention, when the condensate pump trips, the amount of decrease in the feed water flow rate to the steam generator is reduced, the amount of decrease in the water level of the steam generator is suppressed, and continuation of the run-out operation of the condensate pump that continues operation is prevented. can do.

It is a distribution diagram showing steam turbine equipment to which a 1st embodiment of a feed water pump control device of the present invention is applied. It is a block diagram explaining the structure of 1st Embodiment of the feed pump control apparatus of this invention. It is a characteristic view explaining the operation | movement at the time of starting the condensate pump trip preliminary | backup machine in 1st Embodiment of the feed water pump control apparatus of this invention. It is a characteristic view explaining the operation | movement at the time of the condensate pump trip reserve machine non-starting in 2nd Embodiment of the feed water pump control apparatus of this invention. It is a characteristic view explaining the operation | movement at the time of the condensate pump trip reserve machine non-starting in 3rd Embodiment of the feed water pump control apparatus of this invention. It is a characteristic view explaining the operation | movement at the time of the condensate pump trip preliminary machine non-starting in 4th Embodiment of the feed water pump control apparatus of this invention. It is a table | surface figure which shows the example of a setting of the pump driving | running state determination and the maximum flow volume restriction | limiting in each embodiment of the feed water pump control apparatus of this invention.

  Hereinafter, an embodiment of a feed water pump control device of the present invention will be described with reference to the drawings.

  FIG. 1 is a system diagram showing a steam turbine facility to which a first embodiment of a feed water pump control device of the present invention is applied, and FIG. 2 explains the configuration of the first embodiment of the feed water pump control device of the present invention. FIG. 3 is a characteristic diagram for explaining the operation when the condensate pump trip preliminary machine is activated in the first embodiment of the feed pump control device of the present invention.

  In FIG. 1, the steam generated by the steam generator 1 is supplied to the high-pressure turbine 2 through a supply pipe. The steam expanded in the high-pressure turbine 2 is reheated in the moisture separation heater 3 through the steam pipe and supplied to the low-pressure turbine 4. The steam expanded in the low-pressure turbine 4 is condensed by the condenser 5 to become condensate. This condensate is led out from the condenser 5 by a plurality of low-pressure condensate pumps 6 (four in this example) arranged in parallel, and is boosted to a plurality of high-pressure condensate pumps 7 arranged in parallel. (4 in this example). The condensate further boosted by the high-pressure condensate pump 7 is supplied to the low-pressure feed water heater 8 through the feed water pipe. The low-pressure feed water heater 8 heats and raises the condensate supplied by the extracted steam of the low-pressure turbine 4. The heated and heated condensate is supplied to a plurality of water supply pumps 10 (four in this example) arranged in parallel and driven at a variable speed by a variable frequency power supply device 9 and is re-pressurized for high-pressure feed water heating. Supplied to the vessel 12. The high pressure feed water heater 12 heats and raises the temperature of the condensate supplied by the extracted steam of the high pressure turbine 2. The condensate heated and heated is supplied to the steam generator 1.

  On the other hand, the extraction steam from the high-pressure turbine 2 is supplied as heating steam to the moisture separation heater 3 and the high-pressure feed water heater 12 as described above, and exchanges heat with the exhaust steam and feed water of the high-pressure turbine 2, respectively. After that, it becomes drain and is collected in the high pressure drain tank 11 through the drain pipe. In addition, the drain from the exhaust steam of the high-pressure turbine 2 generated by the moisture separation of the moisture separator / heater 3 is also collected in the high-pressure drain tank 11. The drain collected in the high-pressure drain tank 11 is led out from the high-pressure drain tank 11 by a plurality of high-pressure drain pumps 13 (four in this example) arranged in parallel and supplied to the inlet side of the water supply pump 10. Has been.

  The feed water flow rate control to the steam generator 1 in the turbine equipment described above controls the water level of the steam generator 1 based on the water level of the steam generator 1, the amount of steam generated by the steam generator 1, and the feed water flow rate to the steam generator 1. The rotation speed command of the drive motor and the feed water pump 10 is controlled by outputting a rotation speed command to the variable frequency power supply device 9 by the feed water flow rate control device 16 and the feed water pump control device 15.

  As shown in FIG. 2, the feed water pump control device 15 includes a pump operation state determination circuit 14 that determines operation states of the low pressure condensate pump 6, the high pressure condensate pump 7, the feed water pump 10, and the high pressure drain pump 13. A maximum flow rate restriction setting circuit 15A that restricts the maximum value of the rotational speed command to the feed water pump 10 according to the operation state of each pump from the operation state determination circuit 14 is provided. The maximum flow rate restriction setting circuit 15A prevents operation exceeding the capacity of each pump. The limited flow rate of each pump includes a specification point flow rate that allows continuous operation in consideration of a control margin such as flow rate fluctuation in normal operation, and a run-out flow rate that limits the operable time during transition.

  Returning to FIG. 1, the configuration of the low-pressure condensate pump 6, the high-pressure condensate pump 7, and the high-pressure drain pump 13 will be described. Each of these pumps has a capacity of about 33% per unit of the condensate flow rate and the high-pressure drain flow rate when the normal plant water supply flow rate is 100%. Each of these pumps is connected in parallel to each other, and each of the three pumps is operated at a normal plant water supply flow rate of 100%, and one is operated as a spare machine.

  The feed pump 10 driven by the variable frequency power supply 9 has the same configuration, and is a pump having a capacity of about 33% per unit when the normal plant feed flow rate is 100%. It is operated by stand-alone operation, and one is provided as a spare machine.

  During normal operation, if any failure occurs in one of a plurality of low-pressure condensate pumps 6, when one of the failed low-pressure condensate pumps 6 trips, the water supply that can be supplied from the two low-pressure condensate pumps 6. Reduce to flow rate. At this time, if the high-pressure condensate pump 7 that is the downstream pump and the feed pump 10 driven by the variable frequency power supply device 9 are combined as usual and the operation is continued at a feed water flow rate of 100%, the low-pressure condensate pump 6 on the upstream side The low-pressure condensate pump 6 is operated beyond the run-out region due to the flow rate that can be fed, the high-pressure condensate pump 7 on the downstream side, and the feed pump 10 driven by the variable frequency power supply 9. 6 may be damaged. In addition, the high-pressure condensate pump 7 and the feed pump 10 driven by the variable frequency power supply 9 do not secure the required suction pressure, so that cavitation may occur and the downstream pump may be damaged.

  Therefore, in order to eliminate the flow rate imbalance from the upstream side to the downstream side of the water supply system when the pump trips, in this embodiment, the maximum flow rate restriction setting circuit 15A is provided in the water supply pump control device 15. The structure of the feed water pump control apparatus 15 is demonstrated using FIG.

  As shown in FIG. 2, the feed water pump control device 15 includes a pump operation state determination circuit 14, a maximum flow rate restriction setting circuit 15A, and a steam generator output change request circuit 15B. The operation state of the low pressure condensate pump 6, the high pressure condensate pump 7, the feed water pump 10, and the high pressure drain pump 13 is input to the pump operation state determination circuit 14. For example, switching contacts of a power circuit breaker for an electric motor that drives each pump are used. The maximum flow rate restriction setting circuit 15A outputs a rotation speed command of the feed pump 10 to the variable frequency power supply device 9, and the steam generator output change request circuit 15B outputs the steam generator to the steam generator output control device 100. An output change command requesting output change of 1 is output.

  Here, when one of the low pressure condensate pump 6 or the high pressure condensate pump 7 trips, the following trip time control means provided in the feed water pump control device 15 is executed. Depending on the operation state of each condensate pump from the pump operation state determination circuit 14, the feed water pump control device 15 limits the maximum value of the rotational speed command of the feed water pump 6 driven by the variable frequency power supply device 9 to a maximum flow rate restriction setting circuit 15A. A setting change command is output to. As a result, the maximum flow rate restriction setting circuit 15A changes the maximum flow rate restriction value from the specification point flow rate to a runout flow rate that can be operated for a short time during the transition of the pump. As a result, the rotation speed of the feed water pump 10 is reduced and the feed water flow rate is reduced, so that there is no flow rate imbalance between the condensing pumps 6 and 7 of the upstream pump and the feed water pump 10 of the downstream pump.

  Further, when the start-up of the tripped pump is detected, the following return time control means provided in the feed water pump control device 15 is executed. The feed pump control device 15 outputs a setting return command to the maximum flow rate restriction setting circuit 15A. Accordingly, the maximum flow rate restriction setting circuit 15A changes the maximum flow rate restriction value from the runout flow rate to the specification point flow rate. As a result, since the control is transferred to the normal operation state, the mismatch between the required water supply flow rate and the water supply / water supply flow rate for the steam generator 1 can be minimized, and the water level lowering amount of the steam generator 1 can be suppressed. it can.

Next, a setting change example of the maximum flow rate restriction setting circuit 15A when one of the plurality of low-pressure condensate pumps 6 has tripped will be described with reference to FIG.
Here, for convenience of explanation, the specification point flow rate is assumed to be 110% of the plant feed water flow rate, and the runout flow rate is set to 130% of the plant feed water flow rate and the operation time is 2 minutes or less. The run-out flow rate when two low-pressure condensate pumps 6 are operated is 86.8% from 33.3 × 2 × 1.3.

  In FIG. 3, when the pump operation state determination circuit 14 determines a trip of one of the plurality of low-pressure condensate pumps 6, the water supply pump control device 15 performs the operation of the water supply pump 10 driven by the variable frequency power supply device 9. A setting change command is output to the maximum flow rate limit setting circuit 15A that limits the maximum value of the rotation speed command. As a result, the maximum flow rate restriction setting circuit 15A allows the low-pressure condensate pump 6 that can operate for a short time during the transition of the pump from the 110% which is the specification point flow rate of the three low-pressure condensate pumps 6 for the maximum flow rate limit value. This is changed to 86.8%, which is the run-out flow rate for the two units. As a result, the rotation speed of the feed water pump 10 is controlled to be reduced, and the feed water flow rate is reduced. This eliminates flow unbalance between the low pressure condensate pump 6 on the upstream side, the high pressure condensate pump 7 on the downstream side, the high pressure drain pump 13, and the water supply pump 10 driven by the variable frequency power supply device 9. Occurrence is prevented.

  Next, when the pump operation state determination circuit 14 detects the start of the spare machine of the low-pressure condensate pump 6, the feed water pump control device 15 outputs a setting return command to the maximum flow rate restriction setting circuit 15A. As a result, the maximum flow rate restriction setting circuit 15A changes the maximum flow rate restriction value from the 86.8% that is the runout flow rate of the two low-pressure condensate pumps 6 to the specification point flow rate of the three low-pressure condensate pumps 6 operation. Change to 110%. As a result, the rotation speed of the feed water pump 10 is controlled to increase, the feed water flow rate increases, and the control is shifted to the normal operation state. As a result, the plant water supply flow rate can be secured quickly and the amount of decrease in the water level of the steam generator 1 can be reduced.

  According to the above-described first embodiment of the feed water pump control device of the present invention, when the condensate pump 6 is tripped, the amount of decrease in the feed water flow rate to the steam generator 1 is reduced, and the water level drop amount of the steam generator 1 is reduced. And the continuation of the run-out operation of the condensate pump 6 that continues to be operated can be prevented.

  Further, according to the above-described first embodiment of the feed water pump control device of the present invention, the feed water pump control device 15 that controls the rotational speed of the feed water pump 10 driven by the variable frequency power supply device 9 is provided with the low pressure condensate pump 6. When the trip of one of the multiple units is detected, the control at the time of trip is executed to change the maximum flow rate limit value for the rotational speed control command to the feed water pump 10 from the specification point flow rate to the runout flow rate, and the low pressure condensate Since the control at the time of returning the maximum flow rate limit value from the runout flow rate to the specification point flow rate is executed when the start of the spare machine of the pump 6 is detected, one of the low pressure condensate pumps 6 is set. After the trip, the spare machine of the low-pressure condensate pump 6 is activated and the time required for the return-time control for returning to the normal water supply flow rate can be shortened.

  In the present embodiment, as a signal for returning the maximum flow rate restriction to the setting change during normal operation, the spare machine start signal of the low pressure condensate pump 6 is used from the contact signal of the circuit breaker. It is not limited. For example, the low pressure condensate pump 6 may be provided with a rotation speed detection means, and a signal detected by the rotation speed detection means may be output to the pump operation state determination circuit 14 of the feed water pump control device 15. Alternatively, pressure detection means for detecting the pump discharge pressure may be provided on the discharge side, and a signal detected by the pressure detection means may be output to the pump operation state determination circuit 14 in the same manner. Then, the set value determined from the pump start characteristic and these detected values may be compared and calculated to determine the start of the spare machine. By determining the start of the spare machine from the pump start characteristics, the actual control time of the trip control of the feed water pump 10 can be secured, so the possibility of occurrence of operation exceeding the runout flow rate of the low pressure condensate pump 6 is reduced.

Hereinafter, a second embodiment of the feed pump control device of the present invention will be described with reference to the drawings. FIG. 4 is a characteristic diagram for explaining the operation when the condensate pump trip preliminary machine is not started in the second embodiment of the feed pump control device of the present invention. In FIG. 4, the same reference numerals as those shown in FIGS. 1 to 3 are the same parts, and detailed description thereof is omitted.
In the first embodiment, the application in the case where one of the plurality of low-pressure condensate pumps 6 trips and the spare machine is activated has been described. In the present embodiment, the low-pressure condensate pump is used. An operation when one of the plurality of 6 trips and the spare machine does not start will be described. Therefore, the configurations of the turbine equipment, the feed water pump control device 15 and the like are the same as those in the first embodiment.

  In FIG. 4, when the pump operation state determination circuit 14 determines a trip of one of the plurality of low-pressure condensate pumps 6, the water supply pump control device 15 is configured to control the water supply pump 10 driven by the variable frequency power supply device 9. A setting change command is output to the maximum flow rate limit setting circuit 15A that limits the maximum value of the rotation speed command. As a result, the maximum flow rate restriction setting circuit 15A allows the low-pressure condensate pump 6 that can operate for a short time during the transition of the pump from the 110% which is the specification point flow rate of the three low-pressure condensate pumps 6 for the maximum flow rate limit value. This is changed to 86.8%, which is the run-out flow rate for the two units. As a result, the rotation speed of the feed water pump 10 is controlled to be reduced, and the feed water flow rate is reduced.

  After this, if the state where the spare machine of the low-pressure condensate pump 6 is not started continues, the two low-pressure condensate pumps 6 continue to run at the run-out flow rate. There is a fear. Further, when all the low-pressure condensate pumps 6 are tripped, a flow rate imbalance occurs between the low-pressure condensate pump 6 on the upstream side, the high-pressure condensate pump 7 on the downstream side, and the feed pump 10 driven by the variable frequency power supply device 9. However, there is a risk of pump damage due to cavitation operation.

  Therefore, for example, when the pump operation state determination circuit 14 determines that the low pressure condensate pump 6 has not been started from a state where a standby unit start signal is not received even after 5 seconds from the standby unit start command, the water supply pump The control device 15 outputs a setting change command again to the maximum flow rate restriction setting circuit 15A. Thus, the maximum flow rate restriction setting circuit 15A changes the maximum flow rate restriction value from the 86.8% which is the run-out flow rate of the two low-pressure condensate pumps 6 to the specification point flow rate of the two low-pressure condensate pumps 6 operation. Change to a certain 73.3% (33.3 × 2 × 1.1). As a result, it is possible to prevent an overload trip due to exceeding the operation permissible time of the low-pressure condensate pump 6 and a cavitation operation due to a decrease in the suction pressure of the feed water pump 10 driven by the variable frequency power supply device 9.

  According to the second embodiment of the feed water pump control device of the present invention described above, the same effect as that of the first embodiment described above can be obtained, and the spare machine of the low pressure condensate pump 6 is not activated. Even in this case, it is possible to prevent an overload trip of the low-pressure condensate pump 6 and a cavitation operation of the feed water pump 10 that are continuing operation.

Hereinafter, a third embodiment of the feed pump control device of the present invention will be described with reference to the drawings. FIG. 5 is a characteristic diagram for explaining the operation when the condensate pump trip preliminary machine is not started in the third embodiment of the feed pump control device of the present invention. In FIG. 5, the same reference numerals as those shown in FIGS. 1 to 4 are the same parts, and detailed description thereof is omitted.
In the second embodiment, the case where one of the plurality of low-pressure condensate pumps 6 trips and the spare machine does not start has been described. However, in the present embodiment, the spare machine is similarly used. Another embodiment of the operation when is not activated will be described. Therefore, the configurations of the turbine equipment, the feed water pump control device 15 and the like are the same as those in the first embodiment.

  In FIG. 5, when the pump operation state determination circuit 14 determines that one of the plurality of low-pressure condensate pumps 6 has tripped, the operations of the feed water pump control device 15 and the maximum flow rate restriction setting circuit 15A are After the pump operation state determination circuit 14 determines that the spare machine has not been started, the maximum flow rate limit of the feed water pump 10 is set to the specified point flow rate for the two low-pressure condensate pumps 6 that have been operated. It has been changed again.

  As a result, as described above, although the overload trip of the low-pressure condensate pump 6 and the cavitation operation of the feed water pump 10 that can be continued can be prevented, the required feed water flow rate and feed water required by the steam generator 1 can be prevented. There is a problem that the flow rate of water supplied to the steam generator 1 by the pump 10 remains unbalanced, and the possibility of a plant trip due to a drop in the water level of the steam generator 1 occurs.

  Therefore, the feed water pump control device 15 outputs an output change command from the steam generator output change request circuit 15B to the steam generator output control device 100 after the pump operation state determination circuit 14 determines that the spare machine has not been started. Thereby, the steam generator output control apparatus 100 reduces the output of the steam generator 1 to the output below the specification point flow rate for the number of the low-pressure condensate pumps 6 that have been continuously operated. As a result, the required feed water flow rate of the steam generator 1 is reduced, so that the required feed water flow rate required by the steam generator 1 and the low pressure condensate pump 6, the high pressure condensate pump 7, the high pressure drain pump 13 and the feed water pump 10 are reduced. The flow rate of water supplied to the steam generator 1 is balanced. As a result, the occurrence of a plant trip due to a drop in the water level of the steam generator 1 can be prevented.

  According to the third embodiment of the feed water pump control device of the present invention described above, the same effect as the second embodiment described above can be obtained, and the spare machine of the low pressure condensate pump 6 is not activated. Even if it becomes, generation | occurrence | production of the plant trip by the water level fall of the steam generator 1 can be prevented.

Hereinafter, a fourth embodiment of the feed water pump control device of the present invention will be described with reference to the drawings. FIG. 6 is a characteristic diagram for explaining the operation when the condensate pump trip spare machine is not started in the fourth embodiment of the feed pump control device of the present invention. In FIG. 6, the same reference numerals as those shown in FIGS. 1 to 5 are the same parts, and detailed description thereof is omitted.
In the third embodiment, the application in the case where one of the plurality of low-pressure condensate pumps 6 trips and the spare machine does not start has been described. Still another embodiment of the operation when the computer does not start will be described. Therefore, the configurations of the turbine equipment, the feed water pump control device 15 and the like are the same as those in the first embodiment.

  In FIG. 6, when it is determined by the pump operation state determination circuit 14 that one of the low pressure condensate pumps 6 is tripped, the feed water pump control device 15, the maximum flow rate restriction setting circuit 15A, and the steam generator output change The operation of the request circuit 15B is the same as that of the third embodiment, and after the pump operation state determination circuit 14 determines that the spare machine has not been started, the specification point flow rate for two low pressure condensate pumps 6 that have continued to operate. At the same time, the maximum flow rate limit of the feed water pump 10 is changed again, and the output of the steam generator 1 is reduced to an output equal to or lower than the specified point flow rate for the number of low-pressure condensate pumps 6 that have been operated.

  As a result, continuous operation is possible in this plant output state, but there is a problem that the operation capacity per pump of each pump constituting the water supply apparatus is different. That is, while the low-pressure condensate pump 6 is operated with two units, the high-pressure condensate pump 7 and the feed water pump 10 are operated with three units each. If it is a transient operation, it will not be a problem, but if it is continuously operated, these pumps that are operated with 3 units should also be shifted to 2 units.

  Therefore, the feed water pump control device 15 outputs an output change command from the steam generator output change request circuit 15B to the steam generator output control device 100 after the pump operation state determination circuit 14 determines that the spare machine has not been started, One high-pressure condensate pump 7 and one water supply pump 10 are stopped. This balances the operating capacities of the low-pressure condensate pump 6, the high-pressure condensate pump 7, and the feed water pump 10 that have been continuously operated, and the required feed water flow rate and low-pressure condensate required by the steam generator 1. The pump 6, the high-pressure condensate pump 7, the high-pressure drain pump 13, and the feed water pump 10 are balanced with the feed water flow rate supplied to the steam generator 1. As a result, the occurrence of a plant trip due to a drop in the water level of the steam generator 1 can be prevented.

  According to the fourth embodiment of the feed water pump control device of the present invention described above, the same effects as those of the first to third embodiments described above can be obtained.

  In the embodiment of the present invention, the case of one trip among a plurality of low-pressure condensate pumps 6 has been described as an example, but one trip among a plurality of high-pressure condensate pumps 7 is described. The same applies to the maximum water supply flow rate restriction change in FIG. 7 shows an example of the maximum water supply flow rate restriction change in the case of tripping of each of the low-pressure condensate pump 6 and the high-pressure condensate pump 7, standby machine activation or non-activation.

  In the embodiment of the present invention, the case where the present invention is applied to a power plant including a condensate pump having a two-stage configuration has been described. However, the present invention is not limited to this. For example, the present invention can be applied to a power plant including a single-stage condensate pump. Further, although an example in which each pump is configured with four units has been described, for example, a configuration with three units or five units can be applied.

  Furthermore, in the embodiment of the present invention, the case where the present invention is applied to a power plant provided with a drain up by a drain pump has been described, but the present invention is not limited to this. For example, the same effect can be obtained even if the drain is applied to a power generation plant that drains cascade to a downstream feed water heater.

DESCRIPTION OF SYMBOLS 1 Steam generator 2 High pressure turbine 3 Moisture separation heater 4 Low pressure turbine 5 Condenser 6 Low pressure condensate pump 7 High pressure condensate pump 8 Low pressure feed water heater 9 Variable frequency power supply device 10 Feed water pump 11 High pressure drain tank 12 High pressure feed water Heater 13 High-pressure drain pump 14 Pump operation state determination circuit 15 Water supply pump control device 15A Maximum flow rate restriction setting circuit 15B Steam generator output change request circuit 16 Water supply flow rate control device

Claims (3)

A condensate pump installed in parallel to boost the condensate from the condenser, and a plurality of units to further boost the condensate boosted by the condensate pump and supply it to the steam generator. A water supply device having a water supply pump installed in parallel and a variable frequency power supply device that drives a motor of the water supply pump at a variable speed, and outputs a frequency control command to the variable frequency power supply device in the water supply device, A feed water pump control device for controlling the rotation speed of the feed water pump,
When the feed pump control device detects a trip of the condensate pump during operation, it changes the maximum flow rate limit value for the frequency control command to the variable frequency power supply device to a runout flow rate that allows a short-time operation only during a transient state. When detecting the trip time control means and the start-up of the condensate pump spare machine, detecting the return time control means for changing the maximum flow rate limit value from the run-out flow rate to the normal flow rate, and the condensate pump spare machine inactive And a control means for changing the maximum flow rate limit value from the runout flow rate to a normal operation flow rate of the number of condensate pumps that have been operated . In the feed water pump control device according to claim 1 ,
The feed water pump control device comprises control means for outputting a command for requesting a reduction in the output of the steam generator to the output control device of the steam generator when detecting that the spare machine of the condensate pump is not started. A feed water pump control device characterized by that. In the feed water pump control device according to claim 2 ,
The water supply pump control device includes control means for changing the number of operating water pumps so that the number of operating condensate pumps is the same as the number of operating condensate pumps when the condensate pump is not activated. A feed water pump control device characterized by that.

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