JPS59131707A - Control device of turbine by-pass valve - Google Patents

Abstract

PURPOSE:To prevent the abrupt acceleration of steam turbine and the sudden increase of generator output, by arranging a turbine by-pass valve for by-passing the steam turbine, in a plurality of steam turbines. CONSTITUTION:A main steam flows from a steam source 1 to steam turbines 8, 8' through a main steam pressure regulating valve 2, a main steam pipe 5, main steam stop valves 6, 6' and steam control valves 7, 7'. Turbine by-pass valves 12, 12' are provided for by-passing steam turbines 8, 8'. The steam of main steam pipe 5 is allowed to flow directly to condensers 10, 10' when the steam turbine trips or the load of generator is abruptly reduced. Thus, it is possible to prevent the abrupt acceleration of other steam turbines in operation, the sudden increase of generator output or the actuation of main steam release valve 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a control device for a turbine bypass valve of a steam turbine generator.

[Technical background of the invention and its problems]

In plants where main steam is supplied to multiple steam turbine generators from a common main steam pipe, and the main steam pressure is controlled by a main steam pressure control valve installed in the common main steam pipe, the main steam A main steam pressure drop prevention device is installed to prevent water from flowing into the turbine due to a drop in pressure, and a main steam relief valve is installed on the main steam pipe to prevent damage to the turbine due to a rise in main steam pressure. It has been installed.

FIG. 1 shows a conventional configuration of a plant in which main steam is supplied to two steam turbine generators from a common main steam pipe.

The main steam supplied from the steam source 1 is supplied to the main steam pressure control valve 2.
, the main steam pressure detector 3, and the main steam pressure controller 4 to adjust the pressure, and then the steam turbine 8 via the main steam pipe 5, the main steam stop valve 6.6', and the steam control valve 7.7'. .8'.

The steam flowing through the steam turbine 8.8' generates a generator 9.9.
' generates electricity, and steam passing through the steam turbine 8, '8' is condensed into water in a condenser 10,10'.

Now consider the case where both steam turbines 8, 8' are in operation.

When the steam turbine 8 is tripped due to detection of a plant abnormality and the main steam stop valve 6 is suddenly closed, or when the steam control valve 7 is suddenly closed due to a sudden load reduction signal from the generator 9, the main steam Since the supply to the steam turbine 8 is abruptly stopped, the main steam pressure inside the main steam pipe 5 rises rapidly.

Although the main steam pressure detector 3 and the main steam pressure regulator 4 control the main steam pressure regulating valve 2 to prevent the main steam pressure from increasing, it is not possible to suppress a sudden increase in the main steam pressure.

As a result, the steam turbine 8' in operation is suddenly accelerated due to a sudden increase in main steam pressure, and the output of the generator 9' is suddenly increased, which is an unfavorable operating state for the steam turbine generator. Main steam relief valve 11
This has disadvantages in that more main steam is released into the atmosphere, which causes environmental damage and at the same time consumes the life of the main steam relief valve 11.

[Purpose of the invention]

The present invention was made in order to eliminate the above-mentioned drawbacks in the prior art, and it installs a turbine bypass valve that bypasses the steam turbine, and removes the steam in the main steam pipe when the steam turbine is injected (IJ) or when the generator load suddenly decreases. An object of the present invention is to provide a control device for a turbine bypass valve that can prevent rapid acceleration of other operating steam turbines, sudden increase in generator output, and operation of the main steam relief valve by providing a direct flow type to the condenser. shall be.

[Embodiments of the invention]

The present invention will be explained based on the drawings.

FIG. 2 is a system diagram showing an embodiment of the present invention, and shows a configuration in which a turbine bypass valve is installed in a plant where main steam is supplied to two steam turbine generators from a common main steam pipe.

In FIG. 2, 1 to 11.1' to 10' are completely the same as in FIG. 1, and the difference from FIG. 1 is that a turbine bypass valve 12.12' is added.

3 and 4 are diagrams showing an embodiment of the configuration of a control device for a turbine bypass valve according to the present invention.

In both FIGS. 3 and 4, the portion surrounded by a dashed line is the control device for the turbine bypass valve.

The valve opening degree of the turbine bypass valve 12 is controlled by the output signal of the high value priority circuit 13. The output signal of the adder 14, the generator load setting value 15, and the first zero current are connected to the high value priority circuit 13.

When the steam turbine 8 is normally operated, the turbine trip and generator load sudden decrease detection relays are in the OFF' state, and the turbine trip generator load sudden decrease detection relay RD is in the OFF' state.
The B contacts 19, 21 are closed, and the A contacts 2
2.23 is in the open state. The output signal of the adder 14 at this time is the deviation between the main steam pressure value 16 and the maximum main steam pressure setting value 17, and is a negative value. Also, at this time, since the b contact 21 is closed and the a contact β is open, the output signal of the high value priority circuit 13 becomes zero potential U, and the turbine bypass valve 12 becomes fully open.

During normal operation of the steam turbine 8, if the main steam pressure value 16 exceeds the maximum main steam pressure set value 17 and the output signal of the adder 14 becomes a glass value, the output signal of the high value priority circuit 13 is 14, the turbine bypass valve 12 is opened and the opening operation is continued until the output signal of the adder 14 becomes zero.

Therefore, when the steam turbine 8 is in normal operation, the main steam pressure value 16 is controlled by the turbine bypass valve 12 to the maximum main steam pressure setting value 17 or less, and the increase in the main steam pressure has no effect on the steam turbine generator or the main steam relief. Valve activation can be prevented.

When the steam turbine 8 trips or the generator 9 load suddenly decreases, the turbine trip generator load sudden decrease detection relay R1)
is in the ON state, and the b contacts 19, 21, and 21 of the turbine trip generator load sudden decrease detection relay RD are in the open state,
The a-contacts 22 and 23 are closed.

The output signal of the adder 14 at this time is the deviation between the main steam pressure value 16 and the output of the analog memory circuit 18. During normal operation of the steam turbine 8, the main steam pressure value 16 is input to the analog memory circuit 18, so at the moment a turbine trip or a sudden decrease in generator load occurs, the output signal of the adder 14 is It becomes zero.

Therefore, the output signal of the high value priority circuit 13 becomes the generator load set value 15, and the turbine bypass valve 12 is opened for the generator load set value 15 minutes at the moment when the turbine trip or sudden decrease in the generator load occurs. When the steam turbine 8 is in normal operation, the generator load setting value 15 corresponds to the amount of main steam flowing into the steam turbine 8. Therefore, the Fi methane bypass valve 12 switches off the steam at the moment a turbine trip or a sudden decrease in the generator load occurs. Since the same amount of main steam as that flowing into the turbine 8 will flow directly to the condenser 10, the sudden increase in main steam pressure will cause rapid acceleration of other steam turbines in operation and generator output. Sudden increase in main steam relief valve 11
can be prevented from operating.

The generator load setting value 15 is automatically lowered by the IJ knob signal and the generator load sudden decrease signal.
The generator load will gradually decrease to the set value 15, and the turbine bypass valve 12 will be closed accordingly.

On the other hand, since the main steam pressure value 16 gradually increases as the turbine bypass valve 12 is closed, the output signal of the high value priority circuit 13 becomes the deviation between the main steam pressure value 16 and the output of the analog memory circuit 18. , the main steam pressure value 16
is controlled by the turbine bypass valve 12 to match the main steam pressure at the moment when the IJ tube or generator load suddenly decreases, thereby minimizing the influence on other operating turbines.

〔Effect of the invention〕

As explained above, the present invention installs a turbine bypass valve that bypasses the steam turbine, and allows steam in the main steam pipe to directly flow into the condenser when the steam turbine trips or when the generator load suddenly decreases. This has the effect of preventing sudden acceleration of the steam turbine inside, sudden increase in generator output, and activation of the main steam relief valve.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing the equipment configuration of a conventional example, FIG. 2 is a system diagram showing the equipment configuration of the present invention, and FIGS. 3 and 4 are block diagrams showing one embodiment of the present invention. l...Steam source 2...Main steam pressure control valve 3...Main steam pressure detector 4...Main steam pressure regulator 5...Main steam pipe 6.6'...Main steam stop Valve 7.7'... Steam control valve 8.8'... Steam turbine 9.9'... Generator 10.10'...
Condenser 11... Main steam relief valve 12.12'.
...Turbine bypass valve 13...High value priority circuit
14... Adder 15... Generator load setting value ]6.
...Main steam pressure value 17...Maximum main steam pressure setting value 18...Analog memory circuit 19, addition, 2]...B contact No. 22.4 of turbine trip generator load sudden decrease detection relay... Turbine trip generator load sudden decrease detection relay a contact 24...Zero potential agent Patent attorney Noriyuki Chika (1 person) 7
Figure 2 O'

Claims (1)

[Claims] A control device for a turbine bypass valve in a power plant where main steam can be supplied to multiple steam turbine generators from a common main steam pipe, the control device comprising an analog memory circuit that stores main steam pressure values during normal operation of the steam turbine; A maximum main steam pressure setting device, a main steam pressure measuring circuit, a turbine trip generator load sudden decrease detection relay, and an adder are provided, and the output signal of the analog memory circuit selected by the generator load sudden decrease detection relay (17) and a main steam pressure control circuit that calculates the deviation between one of the set values of the maximum main steam pressure setting device and the main steam pressure value measured by the main steam pressure measuring circuit using the adder. , a generator load setter, a zero potential, and the turbine trip generator load sudden decrease detection relay, and a signal of one of the setting value of the 1-1/9-load setter and the above-mentioned zero potential is provided. A high value is selected from the main steam pressure sudden change prevention circuit selected by the turbine trip generator load sudden change detection relay, the output signal of the adder of the main steam pressure control circuit, and the output signal of the main steam pressure sudden change prevention circuit. , a high-value priority circuit that generates an opening signal for a turbine bypass valve; and a turbine bypass for a steam turbine, which prevents an increase in main steam pressure in a main steam pipe when a turbine trips or when a generator load suddenly decreases. Valve control device.