JPS582795A - Reheater control device for atomic power turbine plant - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reheater control device for a nuclear turbine plant that controls the supply of heating steam to a reheater using a portion of the steam supplied to the turbine.

The technology disclosed in Japanese Patent Publication No. 55-38563, which is a conventional example, measures the outlet pressure of a heating steam control valve and controls the heating steam control valve by taking the pressure difference in the turbine cycle.・It reduces thermal stress caused by temperature changes.

゛ This is because the temperature of the cycle steam in the reheater fluctuates greatly during load operation, so by taking the cycle pressure,
The purpose is to represent the temperature of the cycle steam in the reheater and reduce the temperature difference between the cycle steam and heating steam in the reheater.

However, in the conventional reheater control device described above, it is impossible to control the amount of heated steam commensurate with the flow rate from the high-pressure turbine, thereby preventing rapid temperature changes in the steam reheated in the reheater. The disadvantage is that it cannot be done.

An object of the present invention is to provide a reheater control device for a nuclear power turbine plant that prevents overcooling of the reheater and low-pressure turbine and the generation of excessive thermal stress due to large temperature changes.

A feature of the present invention is that a reheater control device for a nuclear turbine plant equipped with a reheater that guides heated steam from a steam source through a pipe having a control valve is equipped with a detector that indicates the power generation output, and a detector that indicates the power generation output. A calculation device that calculates the amount of heated steam to be supplied to the reheater based on the generator output obtained from the detector, and a valve drive electric generator that operates the opening and closing of the control valve according to the output of the calculation device. This makes it possible to always supply the optimum amount of heating steam to the reheater.

Next, a reheater control device for a nuclear power plant, which is an embodiment of the present invention, will be described with reference to the drawings. FIG. 1 shows the steam cycle of a nuclear turbine plant. In the figure, steam generated in a steam generator 1 passes through a main steam stop valve 2 and a steam control valve 3, and is led to a high-pressure turbine 6. The main steam stop valve 2 and the steam control valve 3 are opened and closed by the control device 5 in response to a speed signal from a speed detector 4 of the steam turbine rotor so as to reach a target speed. The steam that did work in the high-pressure turbine 6 and drove the J-pressure turbine is
Since both the temperature has decreased and the humidity in the steam has also increased, the moisture is separated by the moisture separator 7 and then the steam is introduced to the reheater 8. The heat source of the reheater 8 uses steam generated by the steam generator 1 and branches from the upstream side of the main steam stop valve 2. The steam whose temperature has increased by exchanging heat with the heated steam in the reheater 8 is called reheated steam, and is led to the low pressure turbine 9. High pressure turbine 6 and low pressure turbine 9 are coupled to generator 10 and drive generator 10 . Steam that performs work in the low-pressure turbine 9 and generates driving power is led to a condenser 11, condenses to become water, and is led to a feed water heater 12. Heated steam after heat exchange with the reheater is also introduced to this feed water heater 12,
Heat the water from the condenser. The heated water is supplied to the steam generator 1.

A heated steam control valve 14 is installed in the heated steam piping led to the reheater 8, and is controlled to open and close by a control device 16 and a drive device 115.

In other words, the signal of the generator output (detector 1'7) is input to the control device 16, becomes the valve opening signal, and becomes the control valve drive device 1.
5, and the amount of heating steam is controlled by opening and closing the heating steam control valve 14.

The generator output is different from the turbine load and is proportional to the turbine steam flow rate. At low loads, the turbine steam flow rate is low and therefore the reheater heating steam amount may also be low. If the amount of heating steam is left unchanged when the load is reduced,
Looking at the inside of the reheater 8, as the load decreases, the temperature of the steam coming out of the high-pressure turbine 6, that is, the temperature of the heated side flowing into the reheater 8, is reduced to the lower p side, and the heating side steam and the heated side are The side steam temperature difference increases, and stress is generated inside the reheater. Therefore, if the load decreases, the heating steam control valve 1
The temperature of the heated steam is lowered by reducing the opening of No. 4 and lowering the outlet pressure of the valve.

Further, when considering the thermal stress of the rotor of the low pressure turbine 90, a change in the steam temperature at the inlet of the low pressure turbine 90, that is, the steam temperature at the outlet of the reheater becomes a problem. Even if the load decreases significantly and the steam flow rate from the high-pressure turbine 6 decreases, if the heating side steam flow rate is set to 11, the heated side flow rate will decrease.
Since the heating side flow rate remains the same, even if the steam temperature from the high pressure turbine decreases slightly, the reheater outlet steam temperature approaches the heating side steam temperature, and the temperature does not tend to rise. It can be a source of stress for some people. For these reasons, it is desirable that the amount of heating steam supplied to the reheater 8 is increased or decreased depending on the turbine load. At the time of load cutoff, the steam control valve 3 of the turbine suddenly closes to throttle the steam in response to a sudden reduction signal (not shown) of the generator load. At this time, the turbine flow rate suddenly decreases, so it is desirable to reduce the reheater heating steam rise rapidly so that the heating steam does not flow without steam on the heated side. This can be achieved by controlling the opening and closing of the steam control valve 14.

FIG. 2 is a block diagram showing the control mechanism of the reheater described above. The detected generator output signal is converted into an opening/closing signal V for the heating steam control valve 14 by the following calculation within the heating steam control valve 140 controller. An appropriate bias signal B is applied to the generator output signal to the bias setter 16a.

This is because the temperature inside the reheater 8 and the rotor of the low-pressure turbine 9 are low at low loads after startup, such as initial negative IR (about 5%) after merging. Since a large temperature difference occurs when passing through the tube, in order to prevent this, the inflow of heating steam is stopped when the load is below a certain level. Next, the heating steam amount f1 is determined by the function generator 16b for the biased generator output signal. An example of the function generator 16b is shown in FIG. 3, in which the generator output signal after the bias is subtracted is proportional to the control valve flow signal.

Next, from the characteristics of the valve opening degree and valve flow rate of the heating steam control valve 14, using the function generator 16C, a heating steam amount signal f+4h, etc.
Outputs heating steam control valve opening signal V. An example of the function generator 16C is shown in FIG. This valve opening signal is sent to the control valve drive device 15, which drives the control valve.

14 will be controlled to open and close to the required opening degree.

Next, a reheater control device for a nuclear turbine plant, which is another embodiment of the present invention, will be described.

In one embodiment of the present invention, in addition to the generator output, the steam pressure on the downstream side of the heating steam control valve 14 is detected to control the opening degree of the heating steam control valve 14. This embodiment is shown in FIG. To explain only the differences from FIG. 1, the steam pressure detector 18 on the downstream side of the heated steam control valve 14 detects the steam pressure P, and from this, the control device 16 calculates the heated steam flow rate to control the valve. The opening degree is corrected.

FIG. 6 shows a block diagram of the control mechanism. In the example shown in FIG. 6, in addition to that shown in FIG. signal f
O is calculated, the deviation between this signal fo and the heated steam flow rate signal f calculated by the function generator 16b is taken, and the flow rate is corrected by multiplying by a coefficient K. The opening angle is adjusted to catch insects.

Further, the function generator 16C calculates the valve opening signal V from the actual flow rate signal f, and corrects the opening of the control 4P14 by taking the deviation from the valve opening signal obtained from the heated steam flow rate signal f. Even so, the page is small.

According to the present invention, it is possible to realize a reheater control device for a nuclear turbine plant that can prevent overcooling of the reheater and the low-pressure turbine and generation of excessive thermal stress.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing a control device for a nuclear turbine plant that is one embodiment of the present invention, Fig. 2 is a block diagram showing details of the control device in Fig. 1, and Fig. 3 is a block diagram of Fig. 2. Figure 4 is a characteristic diagram of a function generator that calculates the heating steam flow rate shown in the figure, Figure 4 is a characteristic diagram of a function generator that calculates the control valve opening shown in the block diagram of Figure 2, and Figure 5 is a characteristic diagram of a function generator that calculates the control valve opening shown in the block diagram of Figure 2. FIG. 6 is a block diagram showing details of the control device of FIG. 5. FIG. 1...Steam generator, 2...Main steam stop valve, 3...
Steam, regulating valve 1.4... Speed detector, 5... Control device, 6... High pressure turbine, 7... Moisture separator,
・Reheater, 9...Low pressure turbine, 10... Generator,
14... Heating steam control valve, 15... Drive device, 16
...Control device, 16a...Bias setting device, 16b
, 16C...function generator, 16d...flow rate calculator,
17...Load detector, 18...Figure 2 Figure 3 Figure 9 1439 Figure 5

Claims (1)

[Claims] 1. In a reheater control device for a nuclear turbine plant having a reheater that guides heated steam from a steam source through piping equipped with a control valve, an output detector that detects the generator output of the turbine plant. and a calculation device that calculates the heating steam flow rate of the reheater according to the generator output obtained by the detector,
A reheater side installation device for a nuclear turbine plant, characterized in that it is equipped with a valve-driven lid that operates a control valve in accordance with the output of the arithmetic unit. □ 2. A detection device for detecting the state quantity of the heated steam that has passed through the reheater is provided, and the flow rate of the heated steam is calculated by the calculation device based on the detection signal of the detection device and the generator output signal. A reheater control device for a single turbine plant according to claim 1, characterized in that: