JPS62129505A - Steam turbine control device - Google Patents

Abstract

PURPOSE:To prevent the initial load of a steam turbine from being changed with temperatures of a steam governing valve upon joining a generator into a system, by proportionally calculating a change in rotational speed setting before and after joining of the generator with the inverse number of a constant adjusting rate, and adding the result as calculated above to an output setting unit. CONSTITUTION:Before joining a generator 3 into a system, a change in effective opening degree of a steam governing valve 2 with a metal temperature is corrected by a rotational speed setting unit 9. A difference between a rotational speed setting unit 11 after joining of the generator 3 and the rotational speed setting unit 9 before joining of the generator 3 is calculated by a subtractor 15. An output from the subtractor 15 is fed to a calculator 16 to proportionally calculate the output with the inverse number of a constant adjusting rate of a proportional calculator 13, thus obtaining an A-signal. An output from a selector 17 is selected from zero to the A-signal for a fixed period of time by a timer 18 receiving a joining signal. The A-signal is added to an output setting unit 8 to correct a change in rotational speed control output due to the difference between the rotational speed setting units 11 and 9, thus obtaining a C-signal. The C-signal is added to a B-signal generated from the proportional calculator 13 by an adder 14, thus obtaining a control signal for the steam governing valve 2.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a control device for a steam turbine coupled to a synchronous generator.

BACKGROUND OF THE INVENTION As shown in FIG. 4, a conventional steam turbine system consists of a boiler 1, a steam turbine 3, a generator 4, and a condenser 5. The steam is controlled by a steam control valve 2 which operates according to a command, and is supplied to a steam turbine 3, where work is done.

The steam that has done work in the steam turbine 3 is recovered in the condenser 5, and the work done in the steam turbine 3 is transmitted to the generator 4 and obtained as output from the generator 4.

This steam turbine 30 rotation speed and the output of the generator 4 are:
It is controlled by adjusting the steam control valve by a steam turbine control device that receives a signal from the rotation speed detector 6 as a feedback signal.

As shown in FIG. 5, the steam turbine control device 7 includes a subtracter 12, a rotation speed detector 6, a rotation speed setting device 9 before merging of the generator 4, a rotation speed setting device 11 after merging, and a rotation speed setting device 11 after merging. A switch 10 for switching the rotation speed setter by 10°, a proportional controller 13 for controlling the adjustment rate, an output setter 8 and an adder 14,
A signal outputted by the adder 14 so that the rotation speed becomes the rotation speed setting device 9 before combination and the rotation speed setting device 11 after combination;
A signal for controlling the output of the generator 4 after being added is added by the output setting device 8, and the steam control valve 2 is operated by this output to control the rotation speed and output of the steam turbine 3.

In addition, when the generator 4 is attached, the switching device 10 switches the selection from the pre-attached rotation speed setting device 9 to the post-attached rotation speed setting device 11,
The output setting device 8 outputs an output that increases from zero by the initial load amount,
The initial load amount of the generator 4 is controlled.

Problems to be Solved by the Invention In the conventional steam turbine control device 7, when the generator 4 is installed, the pre-installation rotation speed setting device 9 is operated to control the steam turbine 30.
The rotation speed is controlled to synchronize with the rotation speed of the system in which the generator 4 is added. At this time, the steam flow rate passing through the steam regulating valve 2 varies depending on the metal temperature of the steam regulating valve 2, even if the opening degree is the same, so the output of the pre-intake rotation speed setting device 9 is almost always in a constant system. In order to match the rotation speed, the opening degree of the steam control valve 2 must be changed.
When the generator is connected to the grid, the rotation speed is set using switch 1.
0 is a constant value. As a result of the above, after the generator is added, the output of the steam turbine control device 7 becomes constant, and the steam control valve 2 has a constant opening degree. However, for this reason, there is a difference in the effective opening degree depending on the metal temperature of the steam control valve 2, and the amount of steam supplied to the steam turbine 3 changes, resulting in a difference in the initial load amount of the steam turbine 3 after joining. .

Means for Solving the Problems According to the present invention, a signal obtained by calculating the deviation between the rotation speed setting and the actual rotation speed using a regulation rate is added to the output setting as a signal for controlling the rotation speed and output of the steam turbine. In a steam turbine control device, there is provided an arithmetic unit that calculates the deviation between a rotational speed setting and a rated rotational speed by the reciprocal of the adjustment rate, and a combined signal is output for a certain period of time, during which the output of the arithmetic unit is adjusted to the output setting. A steam turbine controller is provided, comprising: a summing device.

When a power generator is added to the grid, the rotation speed setting before the addition is switched to the rotation speed setting after the addition, but by proportionally calculating the change using the reciprocal of the adjustment rate and adding it to the output setting, the steam The correction for changes in the effective opening due to the metal temperature of the control valve is carried over from the pre-incorporation rotation speed setting, making it possible to keep the initial load of the steam turbine constant.

With this method, the change in the rotation speed setting before and after the combination is corrected, so that the correction of the change in the effective opening degree due to the metal temperature of the steam control valve 2 can be utilized even after the combination.

Embodiment According to FIG. 1, the steam turbine control device includes a rotation speed detector 6, a subtractor 12, a rotation speed setting device 9 before merging, and
After joining, rotation speed setting device 11, rotation speed setting switch 10. In addition to the proportional calculator 13, the output setter 8, and the adder 14,
It includes a subtracter 15, a proportional calculator 16, a fixed time timer 18, and a switch 17.

According to the steam turpin control device according to the invention, the generator 3
Before joining the system, the change in the effective opening degree due to the metal temperature of the steam control valve 2 is corrected by the rotation speed setting device 9 before joining, so the rotation speed setting device 11 and the rotation speed setting device 11 The deviation from the pre-inlet rotation speed setting device 9 is determined by the subtractor 15,
A signal A is generated by a calculator 16 which performs a proportional calculation on the signal using the reciprocal of the adjustment rate of the proportional calculator 13. Depending on the input signal, the timer 18 switches the output of the switch 17 to the zero or A signal for a certain period of time, adds this human signal to the output setting device 8, and sets the rotation speed setting device 11 after input and before rotation. The C signal is generated by correcting the change in the rotation speed control output due to the difference in the device 9. This C signal is added to the proportional calculator 130B signal by the adder 14,
This becomes a control signal for the steam control valve 2, which is an output signal of the steam turbine control device.

FIG. 2 shows how the control signal is corrected.

In FIG. 2, the solid line diagram shows the operation of the conventional device, and the broken line shows the operation of the present invention device. It can be seen that after the combination, the output setting is corrected by the A signal (C signal), and this is added to the B signal.

FIG. 3 shows what happens to the initial load amount of the steam turbine when the steam control valve 2 is controlled using the control signal shown in FIG. The example shown in FIG. 3 shows a case where the metal temperature of the steam control valve 2 is low and the effective opening degree is small.

According to the present invention, the signal becomes like a broken line and does not change even at the time of joining, and the specified initial load of the steam turbine is maintained at the originally required initial load amount.

Incidentally, the same effect can be obtained even if the above-mentioned A signal is added to the rotation speed setting device 11 after addition.

Effects of the Invention According to the present invention, the initial load of the steam turbine changes depending on the temperature state of the steam control valve.
By using the post-rotation speed setting and adding the change to the output setting, it is possible to keep the initial load of the steam turbine constant. Furthermore, when the initial load is increased, the steam pressure of the boiler drops significantly, which can be improved by the present invention.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing the steam turbine control device according to the present invention, Fig. 2 is a diagram showing the movement of control signals to explain the control operation of the control device according to the present invention, and Fig. 3 is a system diagram showing the control device according to the present invention. Figure 4 showing the initial load of the steam turbine obtained.
The figure is a system diagram of a turbine generator plant to which the control device of the present invention is applied, and FIG. 5 is a system diagram showing a conventional steam turbine control device. 1. Boiler, 2. Steam control valve, 3. Steam turbine, 4. Generator, 5. Condenser, 6. Rotation speed detector,
7. Steam turbine control device, 8. Output setting device, 9.
・Rotation speed setting device before merging, 10...Rotation speed setting switch, 1
1... Rotation speed setter after addition, 12... Subtractor, J3...
Proportional calculator,] 4...Adder, 15...Subtractor, 16...
・Proportional calculator, 17... Switching device, 18... Fixed time timer. Figure 1 Figure 2 Figure 1 Figure 8 4 Figure 5

Claims (1)

[Claims] In a steam turbine control device, a signal obtained by calculating the deviation between the rotation speed setting and the actual rotation speed using a regulation rate is added to the output setting and used as a signal to control the rotation speed and output of the steam turbine. A steam turbine control comprising: an arithmetic unit that calculates a deviation from the rated rotational speed using a reciprocal of the adjustment rate; and a device that outputs a combined signal for a certain period of time and adds the output of the arithmetic unit to the output setting during that time. Device.