JPH0250006A - Water-supply controller - Google Patents

Abstract

PURPOSE:To secure the flow rate of supply water stably with an alternative supply water pump for starting when one of main supply water pumps gets trouble by providing a change- over device in a control system of supply water regulating valve used for starting and controlling a supply water regulating valve for starting by the control signal from a control system of adjusting valve for the turbine steam used for driving a main supply water pump. CONSTITUTION:At the time of starting, supply water is secured by a supply water pump 17 for electrically starting. A change-over device 51 is situated on the side (a) of a calculator 50 to control the supply water regulating valve 17 for starting so as to make constant the pressure 37 of the supply water at the inlet of a high pressure supply water heater. Next, one of main supply water pumps is operated and then the number of the pumps is changed to two, and a rated load is adopted. The supply water pump 17 for starting is stopped. At this time the change-over device 51 is left as it is and main supply water pumps 15 and 16 are controlled to hold the pressure difference 22 in supply water regulating valves constant. For instance, if the main supply water pump 15 is out of order, the supply water pump 17 for starting is started and the change-over device 51 is changed over to the side (b) of a function calculator 47. With this arrangement the supply water regulating valve 22 is kept constant by controlling the supply water pump 17 for starting and main supply water pump 16.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a water supply control device that controls a water supply pump that supplies water to a steam generator installed in a fast breeder reactor power plant or the like.

(Prior art) In general, a fast breeder reactor power plant consists of a nuclear reactor that uses liquid metal sodium as a coolant, and a primary cooling system that transfers the thermal energy generated within the reactor to an intermediate heat exchanger via a primary coolant. system, a secondary cooling system that transfers the secondary coolant (liquid metal sodium) that has undergone heat exchange with the primary coolant in the intermediate heat exchanger to the steam generator, and a secondary cooling system that transfers the steam generated in the steam generator to the steam turbine. It consists of a water and steam system to be transported.

FIG. 3 is a configuration diagram showing an example of a water/steam system of a fast breeder reactor plant. This water/steam system is provided to drive the steam turbine 2 with the steam generated by the steam generator 1. In FIG. 3, thermal energy generated in a nuclear reactor (not shown) is transferred to a steam generator 1 via a primary coolant and a secondary coolant. The steam generator 1 includes an evaporator 3 and a superheater 4, and exchanges heat with water or steam.

The IK hot pressure steam generated in the superheater 4 is guided to the steam turbine 2 through the main steam stop valve 5 and the steam control valve 6, where it expands to drive the steam turbine 2, and is then generated by the generator 7.
generates electricity. The steam that drove the steam turbine 2 is condensed in a condenser 8 to become condensed water, which is temporarily stored in the condenser 8. Note that a turbine bypass pipe 10 in which a turbine bypass valve 9 is interposed is connected from upstream of the main steam stop valve 5 to the condenser 8 .

The condensate leaving the condenser 8 is guided to the feed water pump 14 through a condensate pump 11, a low pressure feed water heater 12, and a deaerator 13 in this order. Three 50% capacity water pumps 14 are provided in parallel, and are composed of a pair of main water pumps 15 and 16 driven by turbine bleed air, and a starting water pump 17 driven by an electric motor. A starting water supply control valve 18 is provided downstream of the starting water supply pump 17 .

The feed water coming out of the feed water pump 14 passes through a high pressure feed water heater 19 and then branches into three loops, each passing through a feed water control valve 20 and being supplied to the steam generator 1 of each loop.

In this water/steam system, feed water flow control during normal operation involves manipulating the opening degree of the feed water control valve 20 so that the evaporator outlet steam temperature 21 remains constant, and changing the opening degree of the feed water control valve 20 as a result of changes in the feed water control valve opening degree. The water supply flow rate 23 is adjusted by operating the rotation speeds of the main water supply pump 15 and the main water supply pump 16 so that the obtained water supply control valve differential pressure 22 is constant. The rotation speeds of the main water supply pump 15 and the main water supply pump 16 are controlled by controlling the opening degrees of the turbine steam control valves 24 and 25 for driving the water supply pumps, respectively.

Figures 4 (A) and (B) respectively show the water supply control valve vJ.
FIG. 2 is a configuration diagram showing a TLL system and a turbine steam control valve control system for driving a water supply pump.

First, in the feed water control valve control system, the evaporator outlet steam temperature 21 is compared with the evaporator outlet steam temperature setting value 26 determined so that the evaporator outlet steam has a certain degree of superheating, and the proportional integral element 27 controls the temperature. An operation is performed. In this case, in order to compensate for the response delay of the temperature measurement signal, a deviation signal between the feed water flow rate 23 and the feed water flow rate target value 28 is used as an auxiliary signal 29 for improving control characteristics. The auxiliary signal 29 is added to the proportional integral element signal 30, and after a control calculation is performed by the proportional integral element 31, the water supply regulating valve 20 is controlled by the water supply regulating valve control signal 32 from the proportional integral element 31. This water supply regulating valve control system is provided independently for each loop.

Next, the turbine steam control valve control system for driving the water supply pump will be explained. When the water supply 14-node valve 20 operates, the water supply regulating valve differential pressure 22 changes as a result.

The water supply regulating valve differential pressure 22 of each loop is averaged by an averaging element 33, and after this average value is compared with a water supply regulating valve differential pressure set value 34, a proportional integral element 35 performs control calculation. Then, the feed water pump driving turbine steam control valve 24.
25 is controlled to adjust the total water supply flow rate.

On the other hand, the starting water supply control valve control system shown in FIG. 4(C) is as follows:
It is for adjusting the water supply flow rate of the starting water supply pump 17 used at startup when the main water supply pump 15 and main water supply pump 16 cannot be used, and the water supply control valve control system,
It is a control system independent of the feed water pump driving turbine steam control valve 11J Ill system. In this start-up water supply control valve control system, the high pressure water heater inlet water supply pressure is 37
The starting water supply control valve 18 is controlled so that the amount of water is constant.

That is, the high-pressure feed water heater inlet water supply pressure 37 and the high-pressure feed water heater inlet water supply pressure set value 38 are compared, and a control calculation is performed by the proportional integral element 39.
The starting water supply regulating valve 18 is adjusted by the starting water supply regulating valve control signal 40 from the starting water supply regulating valve 9, and the water supply flow rate from the starting water supply pump 17 is adjusted.

(Problems to be Solved by the Invention) The water supply flow rate of the fast breeder reactor power plant is configured to be ensured by the start-up water pump 17 during startup, and by the main water pumps 15 and 16 during normal operation.

However, during normal operation, one of the main water pumps 15 and 16
If the machine becomes malfunctioning, it is not possible to continue the rated operation and only 50% load operation can be performed. Further, even if the starting water supply pump 17 is started, there is a problem that stable operation cannot be performed because the control systems for both pumps are independent.

The present invention was made in consideration of the above circumstances, and even if one main water supply pump is malfunctioning, the water supply flow rate can be increased by operating one main water supply pump and the start-up water pump in parallel. The purpose of the present invention is to provide a water supply control device that can stably secure water supply.

[Structure of the invention]

(Means for Solving the Problems) A water supply control device according to the present invention has a main water supply pump and a starting water pump that supply water from a condenser to a steam generator in a fast breeder reactor power plant, etc. The main feed water pump is installed in parallel with the system piping, and the flow M of the main feed water pump is adjusted by a turbine steam control valve for driving the main feed water pump, while the flow rate of the start water feed pump is adjusted by a start feed water control valve, a main feed water pump driving turbine steam control valve control system that controls the main feed water pump driving turbine steam control valve so that the differential pressure of the feed water control valve that adjusts the feed water flow rate to the steam generator is constant; In a water supply control device, the water supply control system is equipped with a starting water supply regulating valve control system that controls the starting water supply regulating valve so that the inlet water supply pressure of a high-pressure water heater installed downstream of a water supply pump is constant. The start-up feed water control valve control system is equipped with a switch capable of controlling the start-up feed water control valve with a control signal from the main feed water pump driving turbine steam control valve control system.

(Function) If one main water pump malfunctions during normal operation, the remaining main water pump can only supply 50% of the water. In this case, in order to obtain the rated load, it is necessary to start the starting water pump and operate it in parallel with a healthy main water pump.

Therefore, the switching device is operated to control the start-up feedwater control valve using a control signal from the main feedwater pump driving turbine steam control valve control system. Therefore, the main water supply pump and the starting water supply pump can be stably and uniformly operated in parallel to ensure a stable water supply flow rate.

(Embodiment) FIGS. 1(A) and 1(B) are configuration diagrams showing an embodiment of a water supply control device according to the present invention.

Here, since the configurations of the water/steam system and the water supply control valve control system are the same as those of the conventional system, the same parts are given the same reference numerals and a description thereof will be omitted.

The turbine steam control valve control system 42 for driving the water supply pump includes:
An averaging element 33 for calculating the average value of the water supply control valve differential pressure 22 of each loop is provided, and a deviation signal 43 between the average value and the water supply control valve differential pressure set value 34 is input to a calculator 44 such as a proportional integral element. Ru. After calculating the deviation signal 43, the calculator 44 outputs a water supply pump driving turbine rotation speed command signal 45 as a control signal. This feed water pump driving turbine rotation speed command signal 45 is input to the feed water pump driving turbine steam control valve 24.25, and is also input to the starting feed water control valve control system 48 via the function calculator 46.47. It looks like this.

On the other hand, the startup water supply control valve control system 48 controls the high pressure water heater inlet water supply pressure 37 and the high pressure water heater inlet water supply pressure setting value 3.
A computing unit 50 such as a proportional-integral element is provided, which inputs a deviation signal 49 from 8 and performs control calculations. A switching device 51 is connected to this computing device 50, and this switching device 51 is connected to the computing device 50.
Switching is performed between the side a and the function calculator 47 side. Then, the starting water regulating valve 18 is activated by the starting water regulating valve opening signal 52 selected by the switch 51.
The valve opening degree of the valve is adjusted.

Here, since the output of the arithmetic unit 44 is the main water supply pump driving turbine rotation speed command signal 45, it is necessary to convert it into the starting water supply control valve opening signal 52. FIG. 2(A) shows the main water supply pump drive turbine rotation speed command signal 45, where the horizontal axis is the current signal I and the vertical axis is the rotation speed command signal R. In this figure, 4000rpm to 5000rpm
If it corresponds to the water supply flow rate O~100%, then this is determined by the starting water supply control valve opening signal V5 as shown in FIG. 2(B).
It is necessary to convert to 2. A function calculator 46 performs calculations for this conversion.

The solid line in FIG. 2(C) shows the valve opening degree V-flow ff1F characteristic of the starting water supply ag1 moderation valve 18. The function calculator 47 performs calculations to convert this characteristic into a linear characteristic as shown by the broken line.

Next, the operation of the above embodiment will be explained.

During startup, turbine bleed air cannot be used, so
Water supply is ensured by a starting water supply pump 17 driven by an electric motor. At this time, the switch 51 is switched to the computing unit 50 side a, and the start-up feed water adjustment valve 17 is controlled so that the high pressure feed water heater inlet water feed pressure 37 is constant.

As a result, one main water supply pump was operated, and then two main water supply pumps were operated at the rated load.

In this case, the starting water supply pump 17 stops. At this time, the switch 51 is still on the vJ steamer 50 side a, and the main water supply pumps 15 and 16 are on the water supply ii1! ] The control valve differential pressure 22 is controlled to be constant. Therefore, during normal operation, the switch 51 is always on the computing unit 50 side a.

If one main water pump, for example, the main water pump 15, malfunctions during normal operation, the remaining main water pump 16 can only supply 50% of the water.

In this case, in order to obtain the rated load, the starting water supply pump 1
7 and run it in parallel with the healthy main water pump 16. Therefore, the switch @51 is changed to the function operator 47.
Switching to the side seat, the starting water supply pump 17 and the main water supply pump 16 are controlled so that the water supply regulating valve differential pressure 22 becomes constant.

Therefore, according to the water supply control device according to the present invention, the following effects can be obtained.

First, during normal operation, there is a conventional practice of constant control of the high-pressure feed water heating type inlet water supply pressure of the startup feed water pump 17 at startup, and constant control of the differential pressure of the water supply regulating valve of the main water supply pump 15 and 16 during rated operation. Water supply υJtil can be adopted.

In addition, even if one main water supply pump malfunctions during rated operation, by switching the switch 51 of the water supply control device to the function calculator 47 side and starting the startup water supply pump 17,
It becomes possible to stably operate one main water supply pump and the starting water supply pump 17 in parallel, and high-load operation can be continued.

Furthermore, there is an effect that a water supply control device with high operational reliability can be provided.

In the above embodiment, a case has been described in which there is one starting water supply pump 17 with a capacity of 50%, but the same can be applied to a case with two pumps with a capacity of 25%. Further, for example, even in the case where the capacity of the starting water supply pump is one unit with a capacity of 40%, the same can be applied except that the load can only be taken up to 90% during parallel operation.

〔Effect of the invention〕

In the feed water control system 2 according to the present invention, the start feed water control valve control system is equipped with a switch that can control the start feed water II1 mode control valve by a control signal from the main feed water pump driving turbine steam control valve control system. Even if one main water pump malfunctions during normal operation, one main water pump and the start-up water pump can be operated in parallel in a stable and uniform manner, ensuring a stable water supply flow rate. can do.

[Brief explanation of the drawing]

FIGS. 1(A) and (B) are block diagrams showing one embodiment of the water supply control device according to the present invention, and FIGS. 2(A) to (C) are characteristics showing the functions of the function calculator in the above embodiment. Figure 3 is a configuration diagram showing the water and steam system of a fast breeder reactor power plant,
FIGS. 4(A) to 4(C) are configuration diagrams showing a conventional water supply control device. 1...Steam generator, 2...Steam turbine, 14...
・Water supply pump, 15.16... Main water supply pump, 17.
...Start-up water supply pump, 18...Start-up water supply control valve,
19... High-pressure feed water heater, 20... Water supply control valve, 2
4゜25... Turbine steam control valve for driving water supply pump,
42... Turbine steam control valve control system for driving water feed pump, 45... Main feed water pump drive turbine rotation speed command signal, 46.47... Function calculator, 48... Water feed water control valve control system for startup , 51...Switching device, 52...Start-up water supply control valve opening signal. Representative Patent Attorney Nori Chika Ken Shu Ken Maru Daiko Maru 0nA) (mA) (A) (B) (C)

Claims (1)

[Claims] A pair of main water pumps and startup water pumps that supply water from a condenser to a steam generator in a fast breeder reactor power plant, etc.
The main feed water pump is installed in parallel with the steam system piping, and the flow rate of the main feed water pump is adjusted by a turbine steam control valve for driving the main feed water pump, while the flow rate of the start feed water pump is adjusted by a start feed water control valve. a main feed water pump driving turbine steam control valve control system that controls the main feed water pump driving turbine steam control valve so that the differential pressure of the feed water control valve that adjusts the feed water flow rate to the steam generator is constant; In a water supply control device, the water supply control system is equipped with a starting water supply regulating valve control system that controls the starting water supply regulating valve so that the inlet water supply pressure of a high-pressure water heater installed downstream of a water supply pump is constant. A water supply control device, characterized in that the starting water supply regulating valve control system is equipped with a switching device capable of controlling the starting water supply regulating valve by a control signal from the main water pump driving turbine steam control valve control system.