JP3272175B2 - Air extractor operating steam pressure controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam pressure control device for operating a steam type air extractor of a power plant.

[0002]

2. Description of the Related Art A nuclear power plant generally sends steam generated from a nuclear reactor to a steam turbine, converts thermal energy into mechanical (rotational) energy, and further converts it into electric energy by a generator. After the work is completed, the steam is collected by the condenser as condensate. This condensate is boosted by a condensate pump or the like, passes through a low-pressure feedwater heater,
After the pressure is increased by the reactor water supply pump, the water is led to the reactor via a high-pressure water heater as water supply. Here, the steam-type air extractor continuously discharges non-condensable gas flowing into the condenser to maintain the performance of the condenser, and functions to maintain the degree of vacuum of the condenser. ing.

[0003] The air extractor is composed of a steam chamber, a nozzle, an extractor, an exhaust pipe, and a cooler, guides the steam generated by the reactor (hereinafter referred to as working steam) to the steam chamber, and blows it out from the nozzle to expand. By doing so, a high-speed jet is obtained. The high-speed jet vapor imparts kinetic energy to the non-condensed gas flowing into the bleeding chamber, sucks it into the vent pipe, cools it with a cooler, and discharges it out of the system. In order to continuously suck the non-condensable gas from the condenser, it is necessary to guide the working steam to the steam chamber at a certain pressure. As shown in FIG. 4, the pressure regulating valve 1, the pressure detectors 2, 3 and the pressure The pressure is kept constant by providing a pressure controller consisting of the controller 4 and the converter 5. That is, the working steam pressure is detected by the pressure detectors 2 and 3, and the deviation between the pressure signal and the pressure set value signal is compared and obtained by the pressure controller 4. The opening command converts the electric signal into an air signal. The pressure is output to the converter 5 and the control valve 1 is opened and closed, whereby the pressure set in the working steam pressure controller 4 can be maintained.

[0004] Before and after the control valve 1, a steam type air extractor 8,
Stop valves 6, 7 are provided that open prior to activation of 9, 10, 11. In addition, inlet valves 12, 13, 14, 15 are provided at the inlets of the air extractors 8, 9, 10, 11, respectively.

Normally, the starting procedure is to change the pressure set value of the pressure controller 4 from 0 kg / cm ² to 14.0 kg / cm ² in the form of a ramp, and to change the pressure from the pressure control valve 1 to the inlet valves 12, 13, 14, 15. The pressure in the system was 14.0 kg / cm ^2, and then the inlet valves 12, 13, 14, 15
Is used to open the air extractors and to activate the air extractors 8, 9, 10, and 11.

[0006]

SUMMARY OF THE INVENTION Air extractors 8, 9, 1
When starting 0 and 11, the inlet valves 12, 13, 14, and 15 of the air extractors 8, 9, 10, 11 are opened.
Simultaneously with this opening, the working steam is supplied to a plurality of air extractors 8, 9,
As a result, the operating steam pressure, which is kept constant, temporarily drops, which causes a trouble in the starting operation such as an alarm.

Accordingly, an object of the present invention is to provide an air extractor operating steam pressure control device which secures a sufficient amount of operating steam when the air extractor is started to prevent the operating steam pressure from decreasing. Is to do.

[0008]

SUMMARY OF THE INVENTION The present invention provides a control valve for controlling the amount of steam to an air extractor, and an opening to the control valve based on a deviation between a detected steam pressure signal and a pressure set value signal. In an air extractor operating steam pressure control device comprising a degree command signal and an output controller, at start-up, select a pressure set value signal exceeding a specified value that changes in a ramp shape, and then a specified value that changes in a ramp shape A means for selecting a corresponding pressure set value signal and outputting the selected signal to a deviation calculator of the controller is provided.

Further, the present invention selects a first opening set value signal provided via a proportional-integral control arithmetic unit of the controller which changes in a ramp shape at the time of startup, and thereafter, changes the ramp-shaped second opening set value signal. A means for selecting an opening set value signal and outputting the selected signal in preference to the opening command signal is provided.

[0010]

[Function] As a pressure set value signal exceeding the specified value, for example,
Select 14.5 kg / cm ² and change it into a ramp. As the opening of the control valve increases, the amount of working steam to the air extractor at startup increases.

Next, 14.0 kg / cm ² which is a pressure set value signal corresponding to a specified value is selected from 14.5 kg / cm ² . The output is also changed in a ramp shape. The opening of the control valve gradually changes in the closing direction, and the amount of working steam to the air extractor decreases.
Thus, when starting the air extractor, a decrease in the working steam pressure can be prevented, and an alarm can be prevented from occurring.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 2, the pressure detectors 2 and 3 detect the working steam pressure and input it to the pressure controller 4.

The operation detectors 16 and 17 detect the opening and closing operations of the stop valves 6 and 7 and input the detected operations to the pressure controller 4. Further, the motion detectors 18, 19, 20, 21 are provided with the inlet valves 12, 13, 14,
15 opening and closing operations are detected and input to the pressure controller 4.

FIG. 1 shows the details of the pressure controller 4.
The two-input average calculator calculates an average value based on the pressure signals from the pressure detectors 2 and 3. To the deviation calculator 23, a pressure set value signal described later from the set value switch 24 is input together with the pressure signal from the two-input average calculator 22, and a deviation from the input pressure signal is obtained.

The first, second, and third setting devices 26, 27, and 28 are provided with steam pressures of 0 kg / cm ² , 14.5 kg / cm ² , and 14.0 kg / cm ^{2, respectively.}
The equivalent value is output to the set value switch 24 as a pressure set value signal. The set value switch 24 switches the pressure set value signal, and one of the signals is input to the proportional-integral control calculator 25. Note that reference numerals 29 and 30 in the figure indicate change rate limiters.

Next, the operation of the above configuration will be described. When the stop valves 6 and 7 are fully open, the first setter 26
cm ² is selected, and the control valve 1 is fully closed.

Next, when the stop valves 6 and 7 are fully opened, the first setting device
26 from 0 kg / cm ² exceeding the specified value by the second setting device 27
It is switched to 4.5 kg / cm ² via the change rate limiter 29. In other words, the pressure set value signal changes in a ramp shape by the change rate limiter 29, and the control valve 1 operates from the slight opening to the maximum opening through the intermediate opening.

Next, when the inlet valves 12, 13, 14, 15 are fully opened, the pressure is switched to 14.0 kg / cm ² corresponding to the value specified by the third setting device 28 via the rate-of-change limiting device 30. At this time, the change rate limiter 30
As a result, the output of the third setting device 28 gradually changes in a ramp shape, and the control valve 1 operates in the direction to close the opening, and finally the working steam reaches the specified pressure of 14.0 kg / cm ² .

By the above switching operation, the air extractors 8, 9,
The pressure drop at 10 and 11 can be avoided. In the above embodiment, when the pressure set value signal is switched, the abrupt change is suppressed by the change rate limiters 29 and 30, but the output may be changed like a ramp by a ramp function generator.

Another embodiment will be described with reference to FIG. In the present embodiment, the opening command signal for the control valve 1 is output directly to the output side of the proportional-plus-integral control calculator 25 via the signal selector 31.

When controlled by the set value switch 24,
The proportional-integral control arithmetic unit 25 feeds back the output of the signal selector 31 to the “integration” of the proportional-integral control arithmetic unit 25 because the proportional-integral control arithmetic unit 25 underflows or overflows due to the integration effect.

The first and second opening degree setting devices 32 and 33 output not the pressure setting value signal but the control valve opening degree setting value signal. That is, the first opening degree setting device 32 is a proportional-integral control computing device.
Set value changer with 25 output as it is as opening set value signal
Output to 24. As a result, the inlet valve where maximum disturbance occurs
The opening set value signal gradually changes like a ramp when 12, 13, 14, and 15 open. The second opening degree setting device 33 outputs the full opening degree setting value signal via the change rate limiter 29 to change the signal into a ramp shape.

[0023]

As described above, according to the present invention, it is possible to prevent the occurrence of an alarm when starting the air extractor, to eliminate the interruption of the start-up operation, and to make the start-up proceed smoothly. In addition, a decrease in performance due to a decrease in pressure can be prevented, and a vacuum in the condenser can be quickly established.

[Brief description of the drawings]

FIG. 1 is a block diagram of an air extractor operating steam pressure control device according to the present invention.

FIG. 2 is a configuration diagram of an air extractor operating steam pressure control device according to the present invention.

FIG. 3 is a block diagram showing another embodiment of the present invention.

FIG. 4 is a configuration diagram of a conventional air extractor operating steam pressure control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control valve 4 Pressure controller 6,7 Stop valve 8,9,10,11 Air extractor 12,13,14,15 Inlet valve 23 Deviation calculator 24 Set value switch 25 Proportional integration control calculator 31 Signal selector

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F28B 9/10 F01K 9/00

Claims (3)

(57) [Claims] 1. A control valve for controlling an amount of steam to an air extractor, and an opening command signal to the control valve is output based on a deviation between a detected steam pressure signal and a pressure set value signal. In an air extractor operating steam pressure control device comprising a pressure controller, when the plant is started, a pressure set value signal that changes to a ramp and exceeds a specified value is selected, and then a pressure corresponding to a specified value that changes to a ramp is selected. Means for selecting a set value signal and outputting the selected signal to a deviation calculator of the controller; 2. The steam pressure control device for operating an air extractor according to claim 1, wherein a pressure set value signal exceeding a specified value and a pressure value corresponding to the specified value is changed in a ramp shape by a change rate limiter. 3. A control valve for controlling the amount of steam to the air extractor, and outputs an opening command signal to the control valve based on a deviation between the detected steam pressure signal and a pressure set value signal. An air extractor operating steam pressure control device comprising a controller, wherein at start-up, a first opening set value signal given via a proportional-integral control arithmetic unit of the controller, which changes in a ramp shape, is selected; An air extractor operating steam pressure control device, further comprising means for selecting a second opening set value signal that changes in a ramp shape and outputting the selected signal in preference to the opening command signal.