JP2009204255A - Water supply device for steam generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten time from trip of a condensing pump on the upstream side of a water supply device until return to a normal water supply flow rate by starting a reserve machine of the tripped condensing pump. <P>SOLUTION: In the water supply device having the plurality of condensing pumps 7, 9 and a plurality of water feed pumps 11 including reserve machines, when detecting trip of the condensing pump during operation after executing trip time control for outputting a deceleration operation command at setting speed to inverter devices 16 of all of the operated water feed pumps 11, a control device outputs a start command to the reserve machine of the tripped condensing pump and executes return time control for outputting a return command to a normal state to all of the inverter devices 16 of the water feed pumps 11. Each of the inverter devices 16 increases rotating speed of an electric motor of each of the water feed pumps 11 and makes each of the water feed pumps 11 return to normal operation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a water supply device for a steam generator of a power plant, and more particularly to operation control of a water supply device including a water supply pump from a trip of a low pressure or high pressure condensate pump to normal return.

  In nuclear power plants and thermal power plants, steam generated by a steam generator of a nuclear reactor or boiler is driven by a steam turbine to generate electricity, and the steam driven by the steam turbine is cooled by a condenser and condensed. The condensed condensate is boosted with at least one stage of condensate pump (for example, a two-stage condensate pump of a low pressure condensate pump and a high pressure condensate pump), and further boosted with a feed water pump to supply water to the steam generator. It is supposed to be. These condensate pump and feed water pump are each driven by an electric motor, and these electric motors are driven by, for example, full voltage starting by a power source supplied from a high-voltage bus in the station via a circuit breaker. .

  In addition, the condensate pump and the water supply pump are each configured by connecting a plurality of pumps including a spare machine in parallel, and normally, a plurality of pumps excluding the spare machine are operated to supply water. For example, when the condensate pump and the feed water pump are each composed of three units, when the rated feed water flow rate of the power plant is 100%, the capacity per unit of each pump is 50%, and the two units are in normal operation. One is operating as a spare unit. When a failure occurs in the motor that drives the condensate pump during normal operation, the circuit breaker that supplies power to the motor is opened, and the condensate pump is stopped (tripped) to become a spare machine. The predetermined water supply flow rate is ensured by switching.

  However, when the condensate pump that has failed is tripped, the flow rate output from the condensate pump decreases, so if the downstream pump (high pressure condensate pump, feedwater pump) is operated normally, the upstream side and the downstream side The pump flow rate may become unbalanced and cavitation may occur, damaging the pump.

  Therefore, in general, when one of the condensate pumps trips upstream, stop one of the downstream condensate pump and one of the water supply pumps to eliminate the flow rate imbalance between the upstream and downstream pumps. I have to. After balancing the flow rates of the upstream and downstream pumps in this way, the tripped condensate pump spare machine is started at full voltage and the stopped downstream condensate pump and feedwater pump are operated. Is restored to ensure the water supply flow rate to the steam generator.

  On the other hand, control of the feed water flow rate to the steam generator is controlled to a predetermined feed water flow rate required from the power plant, for example, by adjusting the opening of a feed water flow rate adjustment valve provided at the outlet of the feed water pump. Can do.

  However, since a lot of energy is consumed due to the pressure loss caused by the feed water flow rate adjusting valve, the motor for driving the feed water pump is variable speed by a static variable voltage variable frequency power supply device (hereinafter referred to as an inverter device) from the viewpoint of energy saving. It has been proposed to drive (Patent Document 1). According to this, although it becomes possible to control the feed water flow rate by changing the rotation speed of the feed water pump according to the load pattern, Patent Document 1 discloses that after one of the condensate pumps trips upstream. In addition, there is no description about a method of starting the inverter device when returning the operation of the stopped downstream water supply pump.

  That is, when the inverter device for driving the feed water pump is temporarily stopped with the trip of the upstream condensate pump, and the inverter device for driving the feed water pump is restarted with the start of the upstream condensate pump Because of the characteristics of the inverter device, the motor cannot be started by starting all voltages. Therefore, when the feed water pump is restarted, a so-called soft start is performed in which the output voltage and output frequency of the inverter device are increased at a constant rate to gradually increase the rotation speed of the motor. As a result, it takes time for the output flow rate of the feed water pump to reach the specified feed water flow rate (100%) when returning to normal operation after a trip, and during that time, the feed water flow rate is lower than the required flow rate. There is a problem that the water level of the generator is lowered.

  If the capacity of the inverter device is such that the electric motor can handle the starting current for starting all voltages, there is no need to soft start. However, since the starting current for full-voltage starting is several times the rated current, it is not practical in view of economy.

  On the other hand, in Patent Document 2, the output of the inverter device for driving the feed water pump is throttled with the trip of the upstream condensate pump to balance the flow rates of the upstream condensate pump and the downstream feed water pump. Are listed.

Japanese Patent Application No. 57-103940 JP-A-4-132996

  However, Patent Document 2 describes the control of the inverter device for driving the feed water pump in accordance with the trip of the upstream condensate pump. No consideration is given to the control of the rotation speed of the water supply pump when returning to the flow rate during normal operation. Therefore, it takes time to return to normal operation, and during that time, the water level of a steam generator such as a nuclear reactor may decrease.

  The problem to be solved by the present invention is that after the condensate pump on the upstream side of the water supply device of the steam generator trips, the spare machine of the tripped condensate pump is started to return to the normal water supply flow rate. It is to shorten time.

  In order to solve the above-described problems, the water supply device for a steam generator according to the present invention is configured as follows.

  That is, the present invention increases the condensate of the condenser by using at least one stage of a condensate pump driven by an electric motor, further boosts the condensate boosted by the condensate pump, and supplies the steam generator with the electric motor drive. A water supply pump, a circuit breaker for starting up the full-voltage motor of the condensate pump, an inverter device for variable speed driving the motor of the water supply pump, and a control device for controlling the circuit breaker and the inverter device, In the water supply device for the steam generator, the condensate pump and the water supply pump each include a plurality of spare units. In the water supply device of the steam generator, the control device is in operation when detecting the trip of the condensate pump during operation. After executing the trip time control that outputs a deceleration operation command at a set speed to the inverter devices of all the feed pumps of the above, a start command is issued to the spare machine of the condensate pump that has tripped. And performing a return-time control that outputs a return command to a normal state to all the inverter devices of the feed water pump, and the inverter devices increase the rotational speed of the motor of the feed water pump, Each feed pump is returned to normal operation.

  That is, when the upstream condensate pump trips, the inverter device that drives the feed water pump is decelerated to a set speed (for example, 50% of the normal time) to execute the trip time control. As a result, all the water pumps in operation are decelerated without stopping, so when returning to the normal state, the inverter device increases the rotational speed of the water pump motor from that state to normal operation. Since it returns, the rotational speed of a water supply pump can be returned to the speed at the time of normal operation in a short time. This shortens the time from when the upstream condensate pump trips to the time when the tripped condensate pump spare unit is started and returned to the normal water supply flow rate. It can suppress that the water level of a vessel falls.

  In this case, the trip time control reduces the output of the inverter device to an amount equivalent to the feed water flow rate of the feed water pump required when the condensate pump on the upstream side trips, thereby reducing the unbalance of the feed water flow rate of the feed water system. It is desirable to adjust. In other words, the set speed of the inverter in the trip time control is a shared water supply amount that shares the total water supply amount of the condensate pumps during the operation of the final stage upstream of the water supply pump by the number of operation units of the water supply pumps. Set accordingly.

  In addition, the control device can detect a trip of the condensate pump by an open signal of a breaker of an electric motor that drives the condensate pump or establishment of an open condition of the breaker.

  In addition, the control device outputs the return command to the normal state of the inverter device as a turn-on signal for a breaker of a spare machine of the tripped condensate pump (low pressure condensate pump or high pressure condensate pump) or the same circuit breaker. Can be output when the input condition is satisfied. Here, establishment of the closing condition of the circuit breaker may be due to establishment of a restart condition for the motor of the spare machine of the condensate pump that has tripped. Further, the return command to the normal state of the inverter device is a signal indicating that the driving motor for detecting the start of the motor of the condensate pump that has tripped or the rotational speed of the condensate pump is equal to or higher than a set value. Can be output.

  Furthermore, the return command to the normal state of the inverter device may be a signal indicating that the discharge pressure of the condensate pump or the high pressure condensate pump is equal to or higher than a set value. In this case, it is preferable that the inverter device increases the rotation speed of the electric motor of the feed water pump in accordance with the increase in the discharge pressure.

  Alternatively, the return command to the normal state of the inverter device can be a signal indicating that the feed water flow rate of the condensate pump or the high-pressure condensate pump is equal to or higher than a set value. In this case, it is preferable that the inverter device increases the rotational speed of the electric motor of the water supply pump in accordance with the increase in the water supply flow rate.

  In addition, when the pump on the upstream side is tripped and the deceleration operation command is input, the inverter device replaces the inverter device and naturally decelerates the motor of the water supply pump, and the rotational speed of the motor is When the set speed is reached, the inverter device can be activated and held at the set speed.

  Alternatively, the inverter device operates the inverter device in the regenerative operation mode when the deceleration operation command is input, and changes to the normal operation mode when the rotation speed of the motor of the water supply pump reaches the set speed. It is preferable to hold at the set speed. According to this, the flow rate balance control at the time of trip can be performed quickly. In this case, it is preferable that the inverter device is set to the regenerative operation mode only when the voltage of the in-house high-voltage bus connected to the inverter device is monitored by an instrument transformer and the voltage is not more than a specified voltage value. Further, the inverter device is configured such that when the spare machine is started after the condensate pump or the high-pressure condensate pump is tripped, the electric motor of the spare machine is started from the input signal of the circuit breaker of the motor of the spare machine. It is preferable to enter the regenerative operation mode until the start-up is completed.

  According to the present invention, the time from when the condensate pump on the upstream side of the water supply device of the steam generator trips until the spare machine of the tripped condensate pump is started to return to the normal water supply flow rate is shortened. be able to.

  Hereinafter, the present invention will be described based on examples.

  In FIG. 1, the schematic block diagram of the feed condensate system of the nuclear power plant to which one Example of this invention is applied is shown. As shown in the figure, steam generated in the nuclear reactor 1 is guided to a turbine 3 through a steam pipe 2 equipped with a pressure reducing valve or the like, and the turbine 3 is driven to rotate the generator 4 to generate electric power. It has become. The steam that has driven the turbine 3 is cooled by the condenser 5 and returned to the water. The water in the condenser 5 is led to a low-pressure condensate pump 7 (A to C) having a configuration in which three units are connected in parallel via a condenser outlet pipe 6, and is further boosted through a condenser pipe 8. The pressure is increased by being led to a high-pressure condensate pump 9 (A to C) having a configuration in which bases are connected in parallel. The condensate boosted by the high-pressure condensate pump 9 is supplied to a feed water pump 11 (A to C) having a configuration in which three units are connected in parallel via a feed water pump inlet pipe 10. The feed water pump 11 boosts the feed water to the reactor pressure and supplies it to the reactor 1 through the feed water pipe 12. Needless to say, if the nuclear reactor 1 is replaced with a thermal boiler, the configuration of FIG. 1 can be applied to a thermal power plant as it is.

The drive source of the low-pressure condensate pump 7 (A to C) is a low-pressure condensate pump drive motor (hereinafter simply referred to as an electric motor) 13 (A to C), and each motor 13 is for driving a low-pressure condensate pump. It is connected to the in-house high voltage bus 20 via an electric motor circuit breaker (hereinafter simply referred to as a circuit breaker) 21 (A to C), and power is supplied from the bus. That is, each motor 13 is started at the full voltage by the power supply voltage. The drive source of the high-pressure condensate pump 9 (A to C) is a high-pressure condensate pump drive motor (hereinafter simply referred to as “motor”) 14 (A to C), and each motor 14 is a high-pressure condensate pump. It is connected to the in-house high voltage bus 20 via a driving motor circuit breaker (hereinafter simply referred to as a circuit breaker) 22 (A to C), and power is supplied from the bus. That is, as with the low pressure condensate pump 7, each electric motor 14 is started at the full voltage with the power supply voltage. The drive source of the feed pump 11 (A to C) is a feed pump driving motor (hereinafter simply referred to as “motor pump drive motor”). 15 (A to C), and each motor 15 is driven and controlled by a static variable voltage variable frequency power supply device (hereinafter simply referred to as an inverter device) 16 (A to C). Yes. Each inverter device 16 is connected to the in-house high-voltage bus 20 via a feedwater pump drive motor breaker (hereinafter simply referred to as “breaker”) 23 (A to C), and power is supplied from the bus. That is, the feed water pump 11 is driven at a variable speed by the inverter device 16. In addition, although not shown in figure, the water supply control apparatus which controls the circuit breakers 21 and 22 of each electric motor 13 and 14 and the inverter apparatus 16 connected to the circuit breaker 23 is provided.

  Here, the structure of the low pressure condensate pump 7, the high pressure condensate pump 9, and the feed water pump 11 will be described. The low-pressure condensate pump 7 and the high-pressure condensate pump 9 having a configuration in which three units are connected in parallel are 50% output water amount per unit when the normal amount of plant water supply is 100%. Two units are operated and one unit is operated as a spare unit. Similarly, each of the water supply pumps 11 is a pump having an output water amount of 50% per unit, and is normally operated by operating two units, and one unit is a spare unit. The circuit breakers 21, 22 and 23 of the pumps being operated are closed, and the circuit breakers 21, 22 and 23 of the spare pumps are opened.

  On the other hand, when any failure occurs in the motor 13 of one low-pressure condensate pump 7 during normal operation, the water supply control device switches the circuit breaker 21 related to the failed low-pressure condensate pump 7 from closed to open, The failed low-pressure condensate pump 7 is stopped (tripped). For example, if the low-pressure condensate pump 7A is tripped due to a failure during normal operation by two low-pressure condensate pumps 7A and 7B, the plant water supply will be 50%, which is the amount of water that can be supplied from the low-pressure condensate pump 7B. Decrease. At that time, if the high-pressure condensate pumps 9A and 9B and the feed water pumps 11A and 11B, which are the downstream pumps, are continuously operated with a water supply amount of 100%, the upstream low-pressure condensate pump 7 and the downstream side An imbalance occurs in the flow rates of the high-pressure condensate pumps 9A and 9B and the feed water pumps 11A and 11B. That is, since the downstream pump is not supplied with water supply corresponding to the suction flow rate, cavitation may occur due to flow rate imbalance and the 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, the water supply control device has a circuit breaker 21 indicating that one of the upstream low-pressure condensate pumps 7 has tripped. The circuit breaker 22 of the power supply of the downstream high-pressure condensate pump 9 is opened by the opened signal or the failure signal, and one of the two units in operation is stopped. Thereby, the flow rate imbalance between the low-pressure condensate pump 7 of the upstream pump and the high-pressure condensate pump 9 of the downstream pump is eliminated.

  By the way, the circuit breaker 23 of the power supply pump 11 is opened by a signal indicating that the circuit breaker 21 or 22 indicating that one of the low pressure condensate pump 7 or the high pressure condensate pump 9 has tripped is opened or a failure signal. Alternatively, when the inverter device 16 is stopped, the flow rate imbalance can be eliminated. However, as described below, a problem occurs when the low-pressure condensate pump 7 or the high-pressure condensate pump 9 is activated.

  Here, the characteristic configuration and operation of the first embodiment will be described, for example, after the start of the spare machine of the low pressure condensate pump 7 as an example. After the trip of the low-pressure condensate pump 7, the feed water flow rate is reduced. Therefore, the spare machine of the low-pressure condensate pump 7 is activated, the high-pressure condensate pump 9 is activated in response to this activation, and the feed pump 11 is returned to the normal operation. There is a need. Here, in order to make it easy to understand the explanation when the spare machine is started, the low-pressure condensate pump 7, the high-pressure condensate pump 9 and the feed water pump 11 are all operating in A and B, and C is a spare machine. The description will be made assuming that the low-pressure condensate pump 7A has tripped for some reason.

  First, in order to return the feed water flow rate to the level equivalent to the normal operation, a spare machine for the low pressure condensate pump 7C is started in place of the tripped low pressure condensate pump 7A. At this time, the low-pressure condensate pump 7C of the spare machine is activated by turning on the circuit breaker 21C of the low-pressure condensate pump 7C of the spare machine in response to a failure signal of the low-pressure condensate pump 7A or a signal indicating that the circuit breaker 21A is opened. to start. As a result, the all-voltage starting type low-pressure condensate pump 7C is in a state in which a predetermined amount of output water can be discharged relatively immediately.

  Next, the water supply control device detects the activation of the low-pressure condensate pump 7C from the input signal of the circuit breaker 21C, and supplies the circuit breaker 22A of the high-pressure condensate pump 9A that has been stopped to eliminate the flow rate imbalance. Then, the high pressure condensate pump 9A is restarted. Since the high-pressure condensate pump 9A is a full-voltage starting method, the predetermined amount of output water can be discharged relatively quickly, and the flow rates of the low-pressure condensate pump 7 and the high-pressure condensate pump 9 are balanced. Thereby, the inlet flow rate of the feed water pump 11 becomes equivalent to normal operation.

  Here, if one of the water supply pumps 11 is stopped to eliminate the flow rate imbalance, even if the water supply pump 11 is restarted based on the input signal of the circuit breaker 21C of the low pressure condensate pump 7C. Immediately, a predetermined output water amount cannot be discharged. That is, since the feed water pump 11 driven by the inverter device 16 cannot start all voltages due to the characteristics of the inverter device 16, a so-called soft start method is adopted in which the rotational speed is gradually increased from zero. Therefore, for example, once the feed water pump 11A that is driven at a variable speed by the inverter device 16A is stopped when the upstream low pressure condensate pump 7A is tripped, it takes time to restart and reach a predetermined plant feed water amount. In the meantime, the water level of the reactor 1 is greatly lowered.

  Therefore, in the first embodiment, when the low-pressure condensate pump 7A on the upstream side trips, the operating feed water pumps 11A and B are not stopped, and the rotation speeds of the feed water pumps 11A and B are controlled by the inverter devices 16A and B. The output flow rate of each of the feed water pumps 11A and B is controlled at 25% with respect to the normal plant water supply amount of 100%, and the total output flow rate of these feed water pumps 11A and 11B is kept at 50%. Control. That is, the water supply control device outputs an open signal of the circuit breaker 22B of the high pressure condensate pump 9A when detecting a trip of the low pressure condensate pump 7A. Further, a deceleration operation command at a set speed is output to all the inverter devices 16A and B that are in operation.

  Thereby, inverter device 16A, B reduces the rotational speed of water supply pump 11A, B, in order to reduce an output to the water supply flow volume (50% = 25% x2) request | required at the time of upstream pump trip. In other words, the flow rate of the high-pressure condensate pump 9 is about 50% of that during normal operation until the low-pressure condensate pump 7C of the spare machine is started. Further, since the relationship between the pump rotation speed and the pump output flow rate is proportional, the outputs of the inverter devices 16A and B are set so that the rotation speed is 50% for each of the two water supply pumps 11A and B. Reduce. Thereafter, the output is controlled so that the total output flow rate of the two water supply pumps 11A and 11B becomes 50%, and the flow rate imbalance with the upstream side is eliminated.

  Next, control for returning the water supply flow rate to the level equivalent to the normal operation by the inverter devices 16A and 16B will be described. After executing the trip time control, the feed water control device outputs a start command to the circuit breaker 21C to the spare machine of the tripped low pressure condensate pump 7A, and returns to the normal state to the inverter devices 16A, B of the feed water pumps 11A, B. The return command is output and the control at return is executed. That is, the water supply control device outputs a return command to the inverter devices 16A and 16B when the restart of the high-pressure condensate pump 9A that has been stopped is detected by a closing signal of the circuit breaker 22A (breaker open / close state signal 24). Then, the output voltage and the frequency are increased, and the rotation speed of the feed water pumps 11A and 11B is quickly increased to ensure a predetermined plant water supply amount.

  In the above description, the case of the trip of the low pressure condensate pump 7 has been described as an example, but the same applies to the case of the trip of the high pressure condensate pump 9.

  As a result, according to the first embodiment, when the upstream condensate pump trips due to a failure or the like, the output water amount of the feed water pump 11 is reduced by the inverter device 16 without stopping the feed water pump 11. Since control is performed according to the water supply amount of the water pump, problems such as cavitation can be avoided by eliminating flow rate imbalance when the upstream condensate pump trips.

  Furthermore, when the upstream condensate pump spare machine is activated and the upstream condensate pump that has been temporarily stopped is reactivated, this is detected, and the inverter device 16 detects the water supply pump 11. The rotational speed can be rapidly increased to return the output water amount to the normal output water amount, and a predetermined plant water supply amount at the normal time can be quickly secured. As a result, the amount of decrease in the water level of the reactor 1 at the time of restart can be reduced.

  In the first embodiment, when the upstream condensate pump is tripped, the open signal of the circuit breaker 22 of the high pressure condensate pump 9 is used as the upstream condensate pump trip signal for reducing the output of the inverter device 16. However, the present invention is not limited to this, and an open signal of the circuit breaker 21 of the low pressure condensate pump 7, an open condition of the circuit breaker 21, or an open condition of the circuit breaker 22 of the high pressure condensate pump 9 can be applied.

  In the first embodiment, the signal indicating that the circuit breaker 22 of the high-pressure condensate pump 9 is turned on is used as a signal for returning the water supply flow rate to the level corresponding to the normal operation. It is also possible to apply a signal indicating that the restart condition of the motor 14 is satisfied, a drive motor for detecting the start of the motor 14 of the high-pressure condensate pump 9, or a signal in which the rotational speed of the pump exceeds a set value. it can.

  As described above, in the first embodiment, a plurality of motor-driven low-pressure condensate pumps 7 including a spare unit connected to the condenser 5 and a spare commonly connected to the discharge side of the low-pressure condensate pump 7 are used. A plurality of motor-driven high-pressure condensate pumps 9 including a compressor, a plurality of motor-driven feed water pumps 11 including a spare unit commonly connected to the discharge side of the high-pressure condensate pump 9, and each low-pressure condensate pump A plurality of circuit breakers 21 and 22 for starting all voltages of the motors 13 and 14 of each high-pressure condensate pump, a plurality of inverter devices 16 for driving the motors 15 of each water supply pump 11 at variable speeds, and a circuit breaker for each motor In the water supply device that supplies water to the reactor 1 by the water supply pump 11, the water supply control device detects that a trip of the low-pressure condensate pump 7 is in operation. 1 unit When a stop command is output to the high-pressure condensate pump 9 and a trip of one high-pressure condensate pump 9 is detected or when a stop of the high-pressure condensate pump is detected, all of the water supply pumps 11 in operation are After executing a trip time control that outputs a deceleration operation command to the inverter device 16 at a set speed, a start command is output to the spare machine of the tripped low pressure condensate pump 7 or high pressure condensate pump 9 and stopped by a stop command. A restart command is output to the high-pressure condensate pump 9 and a return-time control is executed to output a return command to the normal state to all the inverter devices 16 of the feed water pump 11. The rotation speed of the motor 15 is increased so that each water supply pump 11 is returned to the normal operation, so that the upstream condensate pumps 7 and 9 are tripped. , It is possible to shorten the time required to start to time of returning to return to normal feedwater flow control spare machine tripped condensate pump 7 and 9.

  In the first embodiment, the present invention is applied to a water supply apparatus having a two-stage condensate pump. However, the present invention is not limited to this, and the present invention is the same even when applied to a water supply apparatus having a one-stage condensate pump. The effect of can be produced.

  In FIG. 2, the schematic block diagram of the feed condensate system of the nuclear power plant to which the other Example of this invention is applied is shown. The difference between the second embodiment and the first embodiment is that after the upstream condensate pump trips, the conditions for starting the spare machine and returning the operation of the feed water pump 11 to the normal operation are different. Others are the same as in the first embodiment.

  In the first embodiment, as a condition for returning the water supply pump 11 to the level corresponding to the normal operation, a closing signal of the circuit breaker 22 of the high pressure condensate pump 9, a satisfaction signal of a restart condition of the electric motor 14 of the high pressure condensate pump 9, or a high pressure A drive motor for detecting the activation of the motor 14 of the condensate pump 9 or a signal in which the rotational speed of the pump is equal to or higher than a set value is applied. On the other hand, in the second embodiment, the pressure gauge 25 provided on the discharge side of the high-pressure condensate pump 9 starts the output increase of the inverter device 16 in response to a signal that the discharge pressure is equal to or higher than the set value, The output of the inverter device 16 is increased in accordance with the discharge pressure, and finally the water supply pump 11 is returned to the normal operation.

  FIG. 6 shows the discharge pressure of the high-pressure condensate pump 9 and the discharge pressure of the feed water pump 11 driven by the inverter device 16. As shown in the figure, the operation of the feed water pump 11 can be controlled to match the discharge pressure of the high pressure condensate pump 9, and according to the second embodiment, after the upstream side condensate pump is tripped. It becomes possible to accurately control the water supply flow rate at the time of return.

  In FIG. 2, the discharge pressure of the high-pressure condensate pump 9 is used. Instead, a feed water flow meter is provided on the discharge side of the high-pressure condensate pump 9, and the feed water flow rate is used to increase the output of the inverter device 16. It can also be used as a condition.

  FIG. 3 shows a schematic configuration diagram of a feed and condensate system of a nuclear power plant to which another embodiment of the present invention is applied, and FIGS. 4 and 5 show an internal configuration of the inverter 19 of this embodiment.

  The third embodiment is different from the first embodiment in that the output of the two inverter devices 16 that are the driving source of the feed water pump 11 is output in the first embodiment in response to a signal that the upstream condensing pump of the feed water pump 11 has tripped. In contrast, the third embodiment is configured such that the inverter device 16 is switched to the regenerative operation mode in response to a signal that the upstream condensate pump has tripped.

That is, when the upstream condensate pump (low pressure condensate pump 7, high pressure condensate pump 9) trips, it is desirable from the viewpoint of pump protection to reduce the flow rate of the feed water pump 11 in a short time. Therefore, in the third embodiment, the output of the inverter device 16 is not reduced, but the regenerative operation mode operation is performed, and the electric motor 15 is electrically braked, whereby the flow rate of the water supply pump 11 is reduced in a short time. It is characterized by doing so.
That is, as shown in FIGS. 4 and 5, during normal operation, the inverter device 16 rectifies the converter circuit 31 with AC input supplied from the in-house high-voltage bus 20 through the circuit breaker 23, and smoothes the smoothing capacitor. The direct current circuit 32 is smoothed to direct current, and the inverter circuit 33 is operated as an inverter to be converted into alternating current of an arbitrary voltage and frequency and output to the electric motor 15.

  On the other hand, in the regenerative operation mode, when the output of the inverter device 16 is stopped and the electric motor 15 becomes the power generation side, the regenerative energy of the electric motor 15 is rectified by the inverter circuit 33, and a converter with a power regeneration function is provided. The circuit 31 is operated as an inverter to convert the discharge current of the smoothing capacitor of the DC circuit 32 into AC and return it to the in-house high-voltage bus 20.

  When electric power is regenerated from the inverter device 16 to the in-house high-voltage bus 17 in a state where the in-house high-voltage bus 20 is maintained at the rated voltage in a normal state, there arises a problem that the voltage of the in-house high-voltage bus 20 increases.

  However, when the inverter device 16 is in the regenerative operation, the low-pressure condensate pump 7 or the high-pressure condensate pump 9 is in a start-up state, and the full-voltage-started motor has a current about six times that in normal operation. Therefore, the voltage of the in-house high voltage bus 20 is lower than the rating. Therefore, by regenerating electric power from the inverter device 16, it is possible to reduce the voltage drop width of the in-house high voltage bus 20.

  Therefore, in the third embodiment, as shown in FIG. 3, the voltage of the in-house high voltage bus 20 is monitored by the instrument transformer 26. Then, as shown in FIG. 4, the bus voltage V detected by the instrument transformer 26 is compared with the rated voltage by the comparator 41, and the voltage of the in-house high voltage bus 20 is not lower than the rated voltage, and the circuit breaker When the determination of the open / close state signal 24 by the determination device 42 indicates that the spare machine of the high-pressure condensate pump 9 (or the low-pressure condensate pump 7) is being activated, the regenerative operation of the inverter device 16 is not performed and the normal operation mode is set. 45, the output reduction operation of Examples 1 and 2 is performed.

  On the other hand, as shown in FIG. 5, when the bus voltage V is equal to or lower than the rated voltage as a result of the comparison by the comparator 41, the determination by the determiner 42 of the circuit breaker open / close state signal 24 is as follows. Alternatively, when the start-up of the spare machine of the low-pressure condensate pump 7) is indicated, the inverter device 16 is operated so as to decrease, for example, to a rotation speed equivalent to 50% by the regenerative operation mode 46 of the inverter device 16.

  In addition, it is necessary to limit the regenerative operation mode of the inverter apparatus 16 only at the time of a condensate pump trip. As one of the solutions, the determination unit 42 is provided with a timer, and the regenerative operation mode is set only for the time set by the timer after starting the spare unit. Note that the value of the timer is determined in consideration of both the time until the start-up of the spare machine and the time during which the feed water pump is lowered to a predetermined rotational speed by the regenerative operation mode.

  According to the third embodiment, when the bus voltage V is lower than the rated voltage, the inverter device 16 of the water supply pump 11 can be quickly reduced to a predetermined water supply amount by regenerative operation. Problems can be avoided quickly.

It is a schematic block diagram of the feed condensate system of the nuclear power plant to which Example 1 of the present invention is applied. It is a schematic block diagram of the feed condensate system of the nuclear power plant to which Example 2 of the present invention is applied. It is a schematic block diagram of the feed condensate system of the nuclear power plant to which Example 3 of the present invention is applied. It is a figure explaining the principal part and operation | movement of an inverter of Example 3 of this invention. It is a figure explaining the principal part and operation | movement of an inverter of Example 3 of this invention. It is a figure explaining the change of the discharge pressure of the high pressure condensate pump of Example 2 of this invention, and a feed water pump.

Explanation of symbols

1 ... reactor, 3 ... turbine, 4 ... generator, 5 ... condenser,
7 ... Low pressure condensate pump, 9 ... High pressure condensate pump, 11 ... Feed water pump,
13 ... Electric motor for driving a low-pressure condensate pump, 14 ... Electric motor for driving a high-pressure condensate pump,
15 ... Electric motor for driving the feed pump, 16 ... Static variable voltage variable frequency power supply device,
20 ... Internal high pressure bus, 21 ... Low pressure condensate pump drive motor breaker,
22 ... Electric circuit breaker for driving a high-pressure condensate pump,
23: Electric circuit breaker for driving the feed water pump,
25 ... Discharge pressure gauge 26 ... Instrument transformer

Claims (14)

An electric motor-driven feed pump that boosts the condensate of the condenser with at least one stage of a condensate pump driven by an electric motor, further boosts the condensate boosted by the condensate pump and supplies the steam to the steam generator; A circuit breaker for starting up a full-voltage motor of the condensate pump, an inverter device for driving the motor of the feed water pump at a variable speed, and a control device for controlling the circuit breaker and the inverter device, the condensate pump and the water supply In the water supply device for the steam generator, which is composed of a plurality of pumps each including a spare machine,
When the control device detects a trip of the condensate pump during operation, the control device executes a trip time control that outputs a deceleration operation command according to a set speed to the inverter devices of all the water supply pumps during operation. A start command is output to the spare machine of the condensate pump, and a return time control is executed to output a return command to a normal state to all the inverter devices of the feed water pump,
Each said inverter apparatus raises the rotational speed of the electric motor of each said water supply pump, and returns each said water supply pump to normal operation, The water supply apparatus of the steam generator characterized by the above-mentioned. A plurality of motor-driven low-pressure condensate pumps including a spare unit connected to the condenser, and a plurality of motor-driven high-pressure condensate pumps including a spare unit commonly connected to the discharge side of the low-pressure condensate pump And a plurality of motor-driven feed water pumps including a spare machine commonly connected to the discharge side of the high-pressure condensate pump, and the respective low-pressure condensate pumps and the motors of the high-pressure condensate pumps are activated at full voltage. A plurality of circuit breakers, a plurality of inverter devices that respectively drive the motors of the respective water supply pumps at variable speeds, and a control device that controls the circuit breakers of the motors and the inverter devices. In a water supply device for supplying water,
When the control device detects a trip of the low-pressure condensate pump in operation, the control device outputs a stop command to the one high-pressure condensate pump in operation, and the one of the high-pressure condensate pumps in operation is output. When a trip is detected or when a stop of the high-pressure condensate pump is detected, after executing a trip time control that outputs a deceleration operation command according to a set speed to the inverter devices of all the water supply pumps in operation,
A start command is output to the tripped low-pressure condensate pump or the high-pressure condensate pump spare machine, and a restart command is output to the high-pressure condensate pump stopped by the stop command. Execute return control that outputs a return command to the normal state to the inverter device,
Each said inverter apparatus raises the rotational speed of the electric motor of each said water supply pump, and returns each said water supply pump to normal operation, The water supply apparatus of the steam generator characterized by the above-mentioned. The water supply device for a steam generator according to claim 1 or 2,
The trip time control adjusts the unbalance of the feed water flow rate of the feed water system by reducing the output of the inverter device to the feed water flow rate of the feed water pump required when the upstream condensate pump trips. A water supply device for a steam generator. The water supply device for a steam generator according to claim 1 or 2,
The setting speed of the inverter in the trip time control is set according to the shared water supply amount that is shared by the total number of water supply pumps operating in the condensate pumps operating in the final stage upstream of the water supply pumps. A water supply device for a steam generator. The water supply device for a steam generator according to claim 1,
The control device detects a trip of the condensate pump based on an open signal of a circuit breaker of an electric motor driving the condensate pump or establishment of an open condition of the circuit breaker. . The water supply device for a steam generator according to claim 2,
The controller determines whether the low-pressure condensate pump or the high-pressure condensate pump has tripped or stopped based on an open signal of a breaker of an electric motor that drives the condensate pump or an establishment of an open condition of the breaker. A water supply device for a steam generator. The water supply device for a steam generator according to claim 1 or 2,
The return command to the normal state of the inverter device is output when a closing signal of a circuit breaker of a spare machine of the condensate pump or the high pressure condensate pump or a condition of closing of the circuit breaker is satisfied. Generator water supply device. The water supply device for a steam generator according to claim 1 or 2,
The return command to the normal state of the inverter device is such that the rotational speed of the drive motor or the condensate pump for detecting the start-up of the motor of the condensate pump or the high pressure condensate pump is equal to or higher than a set value. A water supply device for a steam generator, characterized in that it outputs in response to a signal. The water supply device for a steam generator according to claim 1 or 2,
The return command to the normal state of the inverter device is a signal when the discharge pressure of the condensate pump or the high-pressure condensate pump is a set value or more,
The water supply device for a steam generator, wherein the inverter device increases a rotation speed of an electric motor of the water supply pump in accordance with an increase in the discharge pressure. The water supply device for a steam generator according to claim 1 or 2,
The return command to the normal state of the inverter device is a signal that the feed water flow rate of the condensate pump or the high-pressure condensate pump is a set value or more,
The water supply device for a steam generator, wherein the inverter device increases a rotation speed of an electric motor of the water supply pump as the water supply flow rate increases. The water supply device for a steam generator according to claim 1 or 2,
The inverter device, when the deceleration operation command is input, suppresses the inverter device to naturally decelerate the motor of the water supply pump, and when the rotational speed of the motor reaches the set speed, A water supply device for a steam generator, which is activated and held at the set speed. The water supply device for a steam generator according to claim 1 or 2,
The inverter device operates the inverter device in a regenerative operation mode when the deceleration operation command is input, and changes to the normal operation mode when the rotation speed of the motor of the water supply pump reaches a set speed. A steam generator water supply device characterized by being maintained at a speed. The water supply device for a steam generator according to claim 12,
The inverter device monitors the voltage of the high-voltage bus in the station to which the inverter device is connected by an instrument transformer, and enters the regenerative operation mode only when the voltage is below a specified voltage value. Water supply device. The water supply device for a steam generator according to claim 12,
The inverter device starts the motor of the spare machine from the start signal of the circuit breaker of the motor of the spare machine when the spare machine is started after the condensate pump or the high pressure condensate pump trips. A steam generator water supply device that is in the regenerative operation mode until completion.

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