JPH059608B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an output control device for a steam turbine.

[Conventional technology]

In general, steam turbines use high-temperature, high-pressure steam, so instantaneous drastic changes in output are not allowed in terms of steam turbine life and steam consumption. For this reason, in order to make the output setting value of the steam turbine more variable than before, an additional
A setting device is provided.

BACKGROUND ART Conventionally, as this type of secondary setting device for an output setting value, a configuration is known in which an instantaneous response circuit is provided in the secondary setting device for making a permissible instantaneous change in the output. Figure 3 shows the conventional 2
This shows the circuit configuration of the next setting device. That is, in FIG. 3, reference numeral 10 indicates an output secondary setting device, which includes an adder 12 for calculating the deviation between the output setting device R ₁ ^* and the output P ₂ of the secondary setting device 10, an infinite amplifier 14, It is comprised of an integrator 16, an instantaneous response circuit 18, and an adder 20 that adds the respective outputs of the integrator 16 and instantaneous response circuit 18, respectively.
However, in the output secondary setting device 10 configured in this way, the deviation output ΔP obtained by the adder 12 is input to the infinite amplifier 14 to obtain an output of a substantially constant value, and this constant value output is It is input to an integrator 16 and an instantaneous response circuit 18. Therefore, the integrator 16 obtains an output signal that changes at a predetermined rate of change depending on the value of its integration constant. Furthermore, the instantaneous response circuit 18 can respond instantaneously to a certain percentage of the output of the amplifier 14. In this way, the output signals of the integrator 16 and the instantaneous response circuit 18 are added by the adder 20 to obtain the final output command value.
P ₂ can be obtained and the output of the steam turbine can be controlled via a regulating circuit, not shown.

[Problem that the invention seeks to solve]

However, in the conventional output secondary setting device described above, since the instantaneous response circuit 18 is provided after the amplifier 14, the deviation ΔP between the output setting value P ₁ ^* and the output P ₂ of the secondary setting device is Regardless of size,
The output P ₂ of the secondary setter is determined only by the amplification degree of the instantaneous response circuit 18. Therefore, when the deviation ΔP is small, a transient change may occur depending on the amplification degree of the instantaneous response circuit 18, resulting in an unfavorable state such as overshoot of the output _P2 of the secondary setting device. In particular, in turbine generators installed in steel mills and other facilities with large load fluctuations, the allowable instantaneous response may be as high as 30 to 40%, and the conventional circuit configuration described above may not be able to cope with this problem. . It is also possible to use the input signal of the instantaneous response circuit 18 as a signal input to the amplifier 14 instead of the output of the amplifier 14, but in this case, the instantaneous response component is not a constant value but a constant rate of the deviation ΔP, which is not preferable.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to overcome all the problems of the conventional secondary output setting device described above, and to provide a steam turbine equipped with an instantaneous response circuit that can obtain an instantaneous response component of a constant value that can be freely adjusted. To provide an output control device.

[Means for solving problems]

The steam turbine output control device according to the present invention includes:
In a steam turbine output control system equipped with a secondary output setting device to give a change rate to the change in the output setting value of the steam turbine, the maximum allowable instantaneous response is calculated from the deviation between the output setting value and the output value of the secondary setting device. The present invention is characterized by providing an amplifier with a limiter for obtaining an output signal for determining a value, and an adder for adding the output of the amplifier with a limiter and the output of the secondary setting device to obtain a final output setting value. .

In the output control device described above, the output secondary setting device includes an adder that calculates the deviation between the input and output of the secondary setting device, an infinite amplifier that inputs the output of this adder, and an integer that integrates the output of this amplifier. It can be constructed from an integrator.

[Effect]

According to the output control device for a steam turbine according to the present invention, an amplifier with a limiter is provided, separately from the secondary setting device, to determine the deviation between the input and output of the secondary setting device, and to determine the upper limit value of the instantaneous response to this deviation. By adding the output of this amplifier and the output of the secondary setting device to obtain the final output setting value, it responds instantaneously to changes in the output setting value up to a certain value, and responds instantly to changes in the output setting value up to a certain value. For this, output control can be smoothly achieved by changing the rate of change of the secondary setter.

〔Example〕

Next, embodiments of a steam turbine output control device according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the output control device of the present invention, and its main component is an output secondary setting device. For convenience of explanation, the same reference numerals are given to the same components as those of the conventional secondary setting circuit shown in FIG. 3, and detailed explanation thereof will be omitted.

That is, in this example circuit, the output setting value
The difference from the conventional output secondary setting device 1 is that an adder 12 for calculating the deviation ΔP between P ₁ ^* and the output P ₂ of the secondary setting device 10, an infinite amplifier 14, and an integrator 16 are sequentially provided.
Same as 0. However, in the circuit of this embodiment, the output signal of the integrator 16 is input to the secondary setter 1.
0 output P ₂ , and this output P ₂ and the output setting value
An adder 22 for calculating the deviation ΔP of P ₁ ^* , and an amplifier 24 with a limiter for determining the maximum allowable instantaneous response value for the deviation ΔP obtained by the adder 22 are provided,
The output P _x of this amplifier 24 and the secondary setting device 10
The present invention is characterized in that an adder 26 is provided to add the output P ₂ of the adder 26, and the output P ₃ of the adder 26 is used as the final output setting value.

Next, the operation of the circuit of this embodiment constructed as described above will be explained with reference to FIGS. 1 to 5. now,
When the output set value P ₁ ^* changes in a stepwise manner as shown in FIG. 2, the output P ₂ of the secondary setting device 10
has the characteristics as shown in FIG. Therefore, the value of the output deviation ΔP in the adder 22 at this time is:
It changes as shown in FIG. However, for this output deviation ΔP, the maximum allowable instantaneous response value
Since an amplifier 24 with a limiter is provided for determining V ₂₄ , the output P _x of this amplifier 24 changes as shown in FIG. 2 . As a result, the final output setting value P ₃ is the output P ₂ [Figure 2 2]
and the output P _x [FIG. 2 4], and the value changes as shown in FIG. 2 5. As a result, the output command value is such that it responds instantaneously to the step input of the output setting value P ₁ up to the maximum instantaneous allowable value V ₂₄ and responds at the rate of change of the secondary setting device 10 for values higher than that. setting, it is possible to smoothly control the output of the steam turbine.

〔Effect of the invention〕

As is clear from the embodiments described above, according to the present invention, the deviation between the input and output of the secondary setting device is determined;
By configuring a circuit that applies a limiter that determines the maximum allowable instantaneous response value to this deviation, it responds instantaneously to changes in the output set value P ₁ ^* up to the maximum allowable instantaneous response value, and responds to changes exceeding that value. responds at a predetermined rate of change, making it possible to smoothly and freely control the output of the steam turbine.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram of an output setting device showing an embodiment of the main part of the output control device for a steam turbine according to the present invention, and FIGS. 2 1 to 5 are operational waveform diagrams of each part of the circuit shown in FIG. 1. , FIG. 3 is a block circuit diagram showing an example of an output setting device of a conventional output control device. 10...Secondary setter, 12...Adder, 14...
...Infinity amplifier, 16...Integrator, 18...Instantaneous response circuit, 20...Adder, 22...Adder, 2
4...Amplifier with limiter, P ₁ ^* ... Output set value, ΔP... Output set value P ₁ ^* and output of secondary setting device
Deviation from P ₂ , P ₂ ... Output of secondary setting device, P _x ...
Output of amplifier with limiter, P ₃ ...Final output setting value.

Claims (1)

[Scope of Claims] 1. In a steam turbine output control device provided with a secondary output setting device for giving a change rate to a change in the output setting value of the steam turbine, the output setting value and the output value of the secondary setting device are A limiter amplifier is provided to obtain an output signal that determines the maximum allowable instantaneous response value from the deviation of An output control device for a steam turbine, comprising: 2. In the output control device according to claim 1, the output secondary setter includes an adder that calculates the deviation between the input and output of the secondary setter, and an infinite amplifier that receives the output of the adder. and an integrator that integrates the output of the amplifier.