JPS5937231A - Control device of turbine plant - Google Patents

Abstract

PURPOSE:To improve the follow-up property of a bypass valve by a method wherein the amount of flow inproportion to the output required to a turbine is flowed inpreference to a governor valve and the amount corresponding to the subtraction of said amount from a controller output is discountedly allotted to the bypass valve for the control by anticipatory estimate. CONSTITUTION:The output of a controller 40, into which pressure deviation is inputted, is sent to a low value selector 41 and the signal of the output, which subtracts the output of the low value selector 41 from said output of the controller 40, is sent to a subtractor 42 in order to control the bypass valve 7. The output of the low value selector 41 is also sent to a multiplier 30, the output of which is sent to an operating unit 14 for the governor valve 5. The output of the subtractor 42 is sent to a multiplier 27, the output of which is sent to an operating unit 15 for the bypass valve 7. Because the turbine is controlled by anticipatory estimate by means of the bypass valve 7 in such a manner as described above, the control delay of the bypass valve 7 is eliminated, resulting in enabling to prevent the pressure within the inlet piping of the turbine from abruptly charging.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a turbine plant, and particularly to a control device for controlling pressure when it is necessary to send gas through a turbine plant in response to a constant flow load demand regardless of the presence or absence of turbine output. (Flow rate) control device.

FIG. 1 shows an example of a turbine plant to be controlled by the apparatus of the present invention. In FIG. 1, reference numeral 1 indicates a liquid supply pipe;
2 is a flow control valve, 3 is an evaporator, 4 is a turbine inlet pipe,
5 is a governor valve, 6 is a turbine, 7 is a bypass valve, 8 is a turbine exhaust pipe, 9 is a generator, 10 is a flow rate load, 11 is a turbine front pressure detector, 12 is a pressure transmitter, 13 is a control device, 14 .15 is an operating device, 16 is a controller, and 17 is an operating device.

In this turbine downstream / 1 , the liquid fluid conveyed through the liquid supply pipe 1 is supplied to the evaporator 3 through the flow control valve 2 operated by the controller 16 via the operator 17 . It is vaporized and sent to the turbine inlet pipe 4.

During normal operation, the gas in the turbine inlet pipe 4 is
The working fluid is supplied to a turbine 6 through a governor valve 5, and the turbine 6 drives a generator 9. Further, the gas passing through the turbine is discharged to the turbine exhaust pipe 8.

Before the turbine 6 starts up, the turbine inlet piping 4
The gas inside is sent to the Tahin exhaust pipe 8 through the bypass valve 7.

In short, it is assumed that gas needs to be continuously delivered in response to the consumption demand of the fluid load 1o.

In the control system, a turbine front pressure detector 11 is provided to control the pressure of gas in the turbine inlet pipe 4 to a specified value, and a detection signal is sent to a control device 13 by a pressure transmitter 12. The control device 13 has a built-in proportional-integral controller, and based on the deviation between the signal sent from the pressure transmitter 12 and a pressure setting value corresponding to the specified pressure value, the control device 13 determines whether, for example, the turbine front pressure is high. In this case, the output signal of the proportional-integral controller is increased and the output signal is appropriately distributed to the operating devices 14 and 15 according to the operating state. Here, the operating states include (1) turbine power generation operation, (2) turbine start/stop operation, and (3) turbine bypass operation.

FIG. 2 shows a conventional configuration example of the control device 13 shown in FIG.
is a bias setting device, 23 is a changeover switch, 24 is a deviation device, 25 is an adder, 26 is a proportional-integral controller, 27 is a multiplier, 28 is a proportional-integral controller, 29 is a low value selector, 30 is a multiplier shows. Also, the sign φ. V indicates the governor output signal.

The deviation device 21 receives the output signal of the pressure transmitter 12 and the pressure setting device 2.
It receives an output signal of 0, calculates the deviation between the two, and sends the output signals to the (+) side of the deviation device 24 and the adder 25, respectively. The output of the bias setting device 22 is connected to the selector switch 23
The changeover switch 23 connects the input signal to the C terminal and adds it to the adder 25 when the changeover switch 23 is in "turbine power generation operation". , the input signal is connected to the b terminal and transmitted to the (→ side terminal of the deviation device 24).

The calculation result of the deviation device 24 is sent to a proportional-integral controller 26, and the proportional-integral controller 26 sends an output signal to a multiplier 27.

The multiplier 27 sets a multiplier that appropriately determines the relationship between the output signal of the proportional-integral controller 26 and the lift of the bypass valve 7,
The output is sent to the operating device 15 for the bypass valve.

On the other hand, the calculation result of the adder 25 is sent to the proportional-integral controller 28, and the proportional-integral controller 28 sends the output signal to the low value selector 2.
Send on 9th.

Low value selector 29 receives governor output signal φ as another input. 7
The selected signal is compared with the output signal of the proportional-integral controller 28, whichever is smaller, and sent to the multiplier 30.

The multiplier 30 outputs the output signal of the low value selector 29 and the governor valve 5.
A magnification that appropriately determines the relationship with the lift is set, and the output is sent to the governor valve operating device 14.

According to the conventional control device described above, when starting the turbine from the state of turbine bypass operation, the governor output signal φ. 7 can be gradually increased, but the idea is to add the output of the bias setter 22 to the adder 25, equivalently reduce the prepressure set value for the governor valve 5, and entrust the main body of turbine prepressure control to the bypass valve 7. However, the reason why the bias setting device 22 is required is that two proportional-integral controllers for controlling the front pressure are provided independently for the bypass valve and the governor valve. That is, since the bias setting device 22 and the changeover switch 23 are provided as a means for distinguishing which of the bypass valve 7 and the governor valve 5 should be the main body for front pressure control, it is natural that the changeover switch may be changed depending on the operating conditions. It becomes necessary to operate 23.

The original purpose of the control device 130 is to control the turbine front pressure and to control the governor output signal φ. Since the objective is to satisfactorily satisfy both the turbine output control and the turbine output control according to 7, if the bias setting value is changed to one of the two for every operating condition, a problem will occur in which the original purpose of the control cannot be achieved. .

For example, during turbine power generation operation, the bypass valve 7 is fully closed by switching the change-over switch 23 to the b terminal side and equivalently increasing the pressure setting value for the bypass valve 7, so that the governor output signal φ. 7 suddenly decreases, the turbine front pressure increases, and the bypass valve 7 will not open unless it exceeds the specified pressure by an extra bias value, resulting in a disadvantage that the supply of gas to the turbine exhaust pipe 8 is delayed. This has the disadvantage that the delay in gas supply is further aggravated because a cooperative control system that throttles the flow control valve 2 due to an increase in turbine front pressure is generally provided.

Also, providing two independent proportional-integral controllers is clearly an economic loss.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a control device that eliminates the above drawbacks.

A preferred embodiment of the present invention illustrated in FIG. 3 will be described in detail below. In FIG. 3, the same elements as those of the control device shown in FIG. 2 are designated by the same reference numerals.

Regarding the elements in FIG. 3 that are different from those in FIG. 2, reference numeral 40 indicates a proportional-integral controller, 41 indicates a low value selector, and 42 indicates a subtracter.

The deviation device 21 calculates the deviation between the signal sent from the pressure transmitter 12 and the signal sent from the pressure setting device 20, and sends the result (output) to the proportional-integral controller 4o.

The output of the proportional-integral controller 40 is the governor output signal φ. 7 is sent to the low value selector 41 in order to select one of the smaller signals, while the control signal obtained by subtracting the output of the low value selector 41 from the same output is used for the purpose of operating the bypass valve 7. It is sent to the (+) side of the subtracter 42.

The output of the low value selector 41 is sent to the (→ side) of the subtractor 42, while the output is sent to the multiplier 30 for use in operating the governor valve 5.

The multiplier 27 multiplies the input signal by a multiplier that appropriately determines the relationship between the output of the subtractor 42 and the lift of the bypass valve 7, and sends the output to the bypass valve operating device 15.

The multiplier 30 multiplies the input signal by a multiplier that appropriately determines the relationship between the output of the low value selector 41 and the lift of the governor valve 5, and sends the output to the governor valve operating device 14.

The present invention utilizes the output of the only proportional-integral controller 40 originally provided for pressure control in the turbine inlet pipe 4, and generates a turbine output signal φ that is separately determined according to the output required of the turbine. It is predicted that the flow rate equivalent to 7 will flow preferentially to the governor valve 5, and the flow rate equivalent to the flow rate equivalent to the governor valve 5 will be immediately subtracted from the total flow rate equivalent output by the proportional-integral controller 40, and the bypass valve 7 will be distributed at a discount. It provides advance control functions.

Comparing this effect with the conventional one, in the conventional case, the governor output signal φ. Due to the increase in 7, the flow rate of the governor valve 5 increases first by 2,
As a result, the pressure inside the turbine inlet pipe 4 decreases,
Therefore, the proportional integral controller on the bypass valve side (26 in Figure 2)
Because the output of the bypass valve 7 was reduced and the flow rate of the bypass valve 7 was reduced, the reduction of the flow rate of the bypass valve was delayed.
8) even the output of the low value selector (29 in Fig. 2) is reduced.
By the action of the governor output signal φ. There was a problem where 7 could not be used preferentially.

In addition, another advantage of the control performance of the present invention is that the governor output signal φ, such as during a turbine trip. It is also possible to differentially open the bypass valve 7 suddenly when the number 7 suddenly decreases.

Therefore, although the element structure of the present invention is clearly simpler and lower in cost than the conventional one, it has the feature of completely improving the conventional performance in terms of control performance.

FIG. 4 shows the characteristics obtained by the device of the present invention in comparison with the conventional control characteristics. As is clear from FIG. 4, the governor output signal φ. 7, the decrease in the bypass valve flow rate is no longer delayed, and the governor output signal φ. 7, it should be possible to follow the sudden increase in the bypass valve flow rate with a moderate response speed. Furthermore, the pressure within the turbine inlet pipe is controlled to a specified value without sudden fluctuations.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a turbine plant to which the device of the present invention is applied, FIG. 2 is a diagram showing a conventional control device, FIG. 3 is a diagram showing a control device according to the present invention, and FIG. 4 is a diagram showing a control device according to the present invention. FIG. 2 is a diagram showing characteristics of main parts of a turbine plant controlled by the device. 1.Liquid supply pipe, 2.Flow rate control valve, 3.Evaporator, 4
...Turbine inlet piping, 5.Governor valve, 6.Turbine, 7.Bypass valve, 8.Turbine exhaust piping, 9.
- Generator, 10... Flow rate load, 11... Turbine front pressure detector, 12... Pressure transmitter, 13... Control device, 14...
- Operating device, 15... Operating device, 16... Controller, 17...
Operator, 20... Pressure setting device, 21... Deviation device, 22...
- Bias setting device, 23... Selector switch, 24... Deviation device, 25... Adder, 26... Proportional-integral controller, 27
... Multiplier, 28... Proportional-integral controller, 29... Low value selector, 30... Multiplier, 40... Proportional-integral controller, 41
...Low value selector, 42...Subtractor, φ. 7...Governor output signal.

Claims (1)

[Claims] A device for controlling a turbine plant, which includes a governor valve that controls turbine output by adjusting the flow rate passing through the turbine, and a turbine bypass valve that replenishes the insufficient flow rate from the turbine inlet piping to the downstream side of the turbine according to the demand for the flow rate load that exists downstream of the turbine. a proportional-integral controller receiving a turbine pressure deviation signal, the output signal of the proportional-integral controller being applied to the governor valve actuator via a low value selector which is compared with the governor output signal; A control device for a turbine plant, characterized in that the output signal of the integrator is subtracted by the output signal of the low value selector before being applied to a bypass valve operating device.