JPH08232606A - Turbine ground steam pressure controller - Google Patents

Abstract

PURPOSE: To effectively prevent a turbine ground steam-pressure-drop, which occurs in sudden change of a load, by preparing a precedent opening computing element which precedently moves to an optimum opening in accordance with a turbine load signal, and a signal adder which adds the output of a control meter and of the precedent opening computing element. CONSTITUTION: In precedent opening computing element 22, to which the turbine load conditions are sent as a turbine load signals 21, the opening of a ground steam relief control valve 7 or an auxiliary steam supply control valve 5, which matches the load conditions, is set in advance, and a precedent opening command 23 for the control valve 7 is outputted. In this case, if the pressure of a gound steam header 3 varies, the pressure is detected by a pressure detector 10, and the result is sent to a control meter 11 in order to make the corrections. In the controller 11, the output deviation that is obtained by comparing with the value set by a constant pressure setting device 11-1 is sent to a control computing unit 11-2, thereby the precedent opening signals 23 is corrected by an adder 24. As a result, suitable steam supply or relief can be carried out, eve in the case of a sudden load change or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine gland steam pressure control device for a power plant, and more particularly, to power generation for controlling a constant pressure by adjusting an opening degree of an auxiliary steam supply control valve and a gland steam relief control valve. The present invention relates to a steam turbine gland steam pressure control device in a plant.

[0002]

2. Description of the Related Art Generally, a turbine gland steam pressure control device installed in a power plant, as shown in FIG.
A turbine gland steam header 3 that connects the high-pressure turbine gland 1 and the low-pressure turbine gland 2, and an auxiliary steam supply line 4 that guides auxiliary steam to the turbine gland steam header 3.
The auxiliary steam supply control valve 5 for adjusting the amount of auxiliary steam, the relief line 6 for letting out the steam of the turbine ground steam header, the gland steam relief control valve 7 for adjusting the amount of escape steam, and the turbine ground steam header 3. Turbine gland main steam line 8 for supplying turbine main steam, turbine gland main steam control valve 9 for adjusting turbine gland main steam amount, pressure detector 10 for detecting turbine gland steam header pressure, and auxiliary steam supply control valve 5 and a controller 11 for operating the gland steam release control valve 7, and a pressure detector 12 for detecting the turbine gland steam header pressure.
And a controller 13 for operating the turbine ground main steam control valve 9.

Usually, before starting the steam turbine, the vacuum inside the condenser is raised. Therefore, it is necessary to prevent the infiltration of air from the gland portion of the steam turbine. In order to prevent the invasion of air, a steam turbine generally uses steam of a constant pressure and pressurizes the turbine gland to seal the air.

When the steam turbine starts and the load increases, the amount of steam flowing out to the gland part increases due to the high-pressure turbine pressure, so the ground steam of the steam turbine is switched from the auxiliary steam supply to the escape. Go.

The above movement is adjusted by the turbine gland steam pressure control device as follows. That is, since the turbine gland steam flows into the condenser before the start of the steam turbine, the pressure in the turbine gland steam header 3 decreases. In the controller 11, the constant pressure setting device 11-1 and the output signal of the pressure detector 10 are compared by the signal of the pressure detector 10 that detects the pressure in the turbine ground steam header 3, and the deviation is controlled. Calculator 1
It is calculated by 1-2 and sent to the auxiliary steam supply control valve 5 as an output signal of the controller 11.

However, when the pressure of the turbine gland steam header 3 is low, the output signal of the controller 11 decreases because the deviation from the constant pressure setter 11-1 decreases in the downward direction, and the auxiliary steam supply control valve 5 Turbine gland steam header 3 by increasing the opening of
Control to increase the pressure. When the turbine load increases, the amount of steam leakage from the high pressure turbine gland 1 increases, so that the pressure inside the turbine gland steam header 3 increases. This increase in pressure is detected by the pressure detector 10 and sent to the controller 11. In the controller 11, the output signals of the constant pressure setter 11-1 and the pressure detector 10 are compared, and the deviation increases in the ascending direction. For this reason, the output of the control calculator 11-2 also increases and the output signal of the controller 11 also increases, operating the auxiliary steam supply control valve 5 in the closing direction, and further opening the gland steam relief control valve 7 to open the turbine ground. The pressure in the steam header 3 is adjusted to a constant pressure.

[0007]

By the way, in recent power generation plants, the amount of power supply is adjusted by the load of the power generation plant, and the frequency thereof is increasing. (The number of plants that start and stop every day is increasing.) In addition, most plants are equipped with a facility independent operation function. This in-house independent operation function stops the power plant when power transmission becomes impossible due to an accident on the power transmission system side, despite the fact that the power plant itself can operate to meet the required load without any abnormality. Instead of operating the power plant, the power plant is operated at an extremely low load independently in the thermal power plant, and immediately after the recovery of the accident on the power transmission system side, the power generation load (turbine load) is increased to the specified required load and power transmission is restarted. It means the function to wait so that it can be done.

Due to the function of the power plant, once the operation of the power plant is stopped, there is a large start loss at the next start. Therefore, it is particularly important for the thermal economy of the power generation plant to be able to safely continue the operation at an extremely low load without stopping the power generation plant in the event of an unexpected accident on the power transmission system side.

By the command to shift to the in-house isolated operation (hereinafter referred to as the in-house isolated command), the steam control valve of the turbine is narrowed down in a direction to be rapidly closed, and the amount of main steam to the steam turbine is rapidly reduced. Therefore, the amount of steam leaking from the high-pressure turbine gland 1 is drastically reduced, so that the pressure inside the turbine gland steam header 3 is drastically reduced. Then
The turbine gland steam pressure control device moves the gland steam relief control valve 7 in the closing direction and the auxiliary steam supply control valve 5 in the opening direction in the direction of recovering the pressure that is drastically decreased, and thereby the pressure of the turbine gland steam header 3 is reduced. Works to secure.

However, the auxiliary steam supply control valve 5 and the gland steam release control valve 7 are operated by the output signal of the controller 11, and the turbine is operated by the control calculator 11-2 of the controller 11. Because of the deviation between the pressure of the gland steam header 3 and the set pressure of the constant pressure setting device 11-1, the control valve cannot operate unless the pressure of the turbine gland steam header 3 is significantly reduced.

When the pressure in the turbine gland steam header 3 is greatly reduced, air is drawn from the low pressure turbine gland 2 by the condenser, and as a result, the turbine cannot be continuously operated and the power plant is stopped.
That is, how quickly the gland steam escape control valve 7
Is closed and the auxiliary steam supply control valve 5 is opened to prevent the pressure in the turbine gland steam header 3 from decreasing.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a turbine ground steam pressure control device with a preceding signal condition for reducing the turbine ground steam pressure that occurs during in-house single operation or during a sudden load change. The purpose of the present invention is to provide a turbine gland steam pressure control device that secures the turbine gland steam pressure.

[0013]

In order to achieve the above object, the first aspect of the present invention provides an auxiliary steam supply control valve and a gland steam relief control valve for securing a steam turbine gland pressure, and a turbine gland steam. A pressure detector for detecting the pressure, a pressure regulator for keeping the gland steam constant, and a turbine gland steam pressure control device configured to open and close both of the control valves by a signal from the pressure regulator, in accordance with a turbine load signal. Turbine gland steam at the time of a load change, comprising a preceding opening calculator that precedently shifts to the optimum opening, and a signal adder that adds the controller output and the preceding opening calculator output The turbine gland steam pressure control device according to claim 1 of the present invention is characterized in that control is performed so as to prevent pressure fluctuations. The optimum opening of the control valve is calculated from the turbine inlet steam pressure by the preceding opening calculator, and the controller output and the preceding opening calculation output are added by the signal adder It is characterized by controlling to prevent turbine gland steam pressure fluctuations.

According to a third aspect of the present invention, in the turbine gland steam pressure control device according to the first aspect, the controller output and the preceding opening degree are calculated by the preceding opening degree computing device in response to a shift command to the in-house isolated operation and a turbine stop command. It is characterized in that the calculation output is added by a signal adder to control so as to prevent the fluctuation of the turbine ground steam pressure at the time of shifting to the independent operation in the plant and at the time of stopping the turbine.

According to a fourth aspect of the present invention, in the turbine gland steam pressure control apparatus according to the third aspect, the preceding signal is temporarily replaced with the output value of the controller, and then the adjustment signal is started from the value after the replacement. It is characterized by a signal replacement device.

[0016]

According to the first aspect of the present invention, the turbine gland steam pressure sharply decreases during a single island operation or a sudden load change, and a control calculation output signal due to a deviation between the pressure of the turbine gland steam header and a constant set value is generated. With this alone, it is not possible to immediately bring the gland steam relief control valve and auxiliary steam supply control valve to the optimum control valve opening, so the turbine gland steam pressure temporarily and suddenly drops, and air is drawn in from the turbine gland part. Turbine operation cannot continue.

Therefore, the turbine load condition is constantly monitored to predict (supply or release) the ground steam condition suitable for the load condition, and the opening degrees of the ground steam relief control valve and the auxiliary steam supply valve are adjusted. When the load suddenly drops by deciding and moving, the gland steam relief control valve is closed immediately and the auxiliary steam control valve is opened.

By controlling in this way, even in the case of independent operation in the plant or a sudden load change, it is possible to continue the operation without lowering the gland steam pressure by going to the optimum control valve opening in advance. And stable control can be performed.

According to the second aspect of the present invention, the amount of steam leakage from the high pressure turbine gland varies depending on the turbine inlet steam pressure during the islanding operation alone or during a sudden load change. Stable control can be performed by calculating the required steam flow rate and determining and moving the openings of the gland steam release control valve and auxiliary steam supply control valve.

Further, claim 3 or claim 4 of the present invention.
According to the in-house operation command and turbine stop command, by quickly switching the ground steam escape adjustment supply adjustment during in-house operation alone or turbine stop,
The operation state can be stopped stably or safely even when the island is operated independently or when the turbine is stopped.

[0021]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a configuration diagram of a first embodiment (corresponding to claim 1) of the present invention. In addition, the same parts as those in the conventional example described above and shown in FIG.

In the figure, the turbine load state is sent to the preceding opening calculator 22 as a turbine load signal 21. In the preceding opening degree computing unit 22, the opening degree of the gland steam escape adjusting valve 7 or the auxiliary steam supply adjusting valve 5 that matches the load state is preset, and the preceding opening degree command 23 of the adjusting valve that matches the load signal 21 is set. Is output from the preceding opening calculator 22.

On the other hand, even in the gland steam escape control valve 7 or the auxiliary steam supply control valve 5 adjusted by the preceding opening command 23, the pressure is adjusted in order to make a correction when the pressure in the gland steam header 3 changes. The detector 10 detects the pressure of the turbine gland steam header 3 and sends it to the controller 11. In the controller 11, the output deviation compared with the set value by the constant pressure setter 11-1 is sent to the control calculator 11-2 and corrected by the adder 24 so as to supplement the preceding opening signal 23.

In the state of the turbine gland control device at the rated load, the auxiliary steam supply control valve 5 is fully closed and the gland steam relief control valve 7 is open. In this state, if an on-site islanding operation command, a turbine stop command, or a sudden load change occurs, the high-pressure turbine gland leakage amount will drastically decrease, and the gland steam pressure will temporarily and drastically decrease. In such a case, the gland steam pressure control device tries to operate so as to keep the gland steam pressure at a constant value, but it does not happen in time, resulting in air infiltration from the turbine gland portion due to a decrease in gland steam pressure.

In order to prevent this series of operations, the control valve openings of the ground steam relief control valve 7 and the auxiliary steam supply control valve 5 are set in advance in the preceding opening calculator 22 by the turbine load signal 21. By setting it, it becomes possible to always supply or escape the steam appropriately even when the load fluctuates rapidly and the island is operated independently.

Further, even if there is some deviation in the preceding opening calculation value, the pressure in the turbine ground steam header 3 is
Since the controller 11 corrects the changed amount and the added amount is added to the preceding opening signal 23 by the adder 24, the constant pressure control of the ground steam is always possible.

As described above, according to the present embodiment, the turbine gland steam pressure control, that is, the addition of the preceding opening degree by the load signal, reduces the gland steam pressure even in the island operation alone or during a sudden load change. It can be prevented to protect the power plant from shutting down.

FIG. 2 is a block diagram of a second embodiment (corresponding to claim 2) of the present invention. The same parts as those in the embodiment shown in FIG. 1 are designated by the same reference numerals, and the duplicated description will be omitted. In the figure, the turbine inlet steam pressure signal 32 for detecting the turbine inlet steam pressure is set in advance in the preceding opening calculator 33 to set the gland steam leakage amount corresponding to the inlet steam pressure. An opening signal of the grand steam escape control valve 7 or the auxiliary steam supply control valve 5 corresponding to the amount of steam leakage is output from the preceding opening calculator 33.

Then, in order to prevent a series of operations of lowering the gland steam pressure, the amount of steam leaking from the high pressure turbine gland is predicted from the turbine inlet steam pressure, and the preceding opening degree calculation is performed so as to maintain the amount of steam necessary for the gland steam. By setting the control valve opening degrees of the gland steam relief control valve 7 and the auxiliary steam supply control valve 5 by the device 33, even when the load fluctuates abruptly and the island operates independently, the proper steam supply or relief can always be performed. It will be possible.

Further, even if the preceding opening calculation value is slightly deviated, the controller 11 corrects the correction of the change in the pressure of the turbine ground steam header 3, and the preceding opening signal 3
Since it is added to 4 by the adder 35, it is always possible to control the constant pressure of the ground steam.

As described above, according to the present embodiment, the turbine gland steam pressure control, that is, the addition of the preceding opening degree by the turbine inlet steam pressure, prevents the gland steam pressure from being lowered even during a single operation in the plant or a sudden load change. Thus, it is possible to protect the stoppage of the power plant.

FIG. 3 is a block diagram of the third embodiment of the present invention. The same parts as those in the embodiment shown in FIG. 1 are designated by the same reference numerals, and the duplicated description will be omitted. In the figure, a signal is output from the preceding opening setter 42 in response to an in-house isolated operation command or a turbine stop command 41. The output signal is sent to the change rate limiter 43 and the high price priority device 44. In the change rate limiter 43, the signal increase up to the preceding opening set value is calculated and output so as to change at a constant change rate. Further, since the high value priority device 44 preferentially outputs a signal having a higher signal value, the signal rapidly changes in the increasing direction and changes in a constant changing rate in the decreasing direction. The preceding opening signal 45 is sent to the subtractor 46 and is corrected by the controller 11.

In order to prevent a series of operations of lowering the ground steam pressure, the control valve openings of the ground steam relief control valve 7 and the auxiliary steam supply control valve 5 are set in advance according to the in-house single command and the turbine stop command 41. By setting with the setting device 42, it is possible to always supply or release the appropriate steam even when the island is operated independently or the turbine is stopped.

Further, by operating the preceding opening set value and the output value of the control calculator 11-2 of the controller 11 by the subtractor 46, constant pressure control can be performed even when switching to the independent operation in the plant or when the turbine is stopped. It is made possible.

As described above, according to the present embodiment, the turbine gland steam pressure control, that is, the preceding opening degree setting based on the in-house isolated operation command or the turbine stop command, reduces the gland steam pressure even during the in-house isolated operation or the turbine stop. It will prevent and protect the power plant shutdown.

FIG. 4 is a block diagram of the fourth embodiment of the present invention. The same parts as those in the embodiment shown in FIG. 1 are designated by the same reference numerals, and the duplicated description will be omitted. In the figure, when the on-site isolated operation command or the turbine stop command 41 is input to the signal pulse generator 51, the preceding opening setting signal 52 is transmitted only for one pulse, and this pulse signal value is used as the temporary signal replacer 53. By changing the control valve opening command 50 to
The gland steam release control valve 7 is moved in the closing direction, and the auxiliary steam supply valve 5 is moved in the opening direction. When the output signal of the signal pulse generator 51 disappears, the temporary signal replacer 53 causes the controller 1
Since the output of the control calculator 11-2 of No. 1 is replaced with the preceding opening setting, the adjustment valve opening command 54 starts to be adjusted from the preceding opening setting signal 52.

In order to prevent a series of operations of the ground steam pressure drop, the necessary control valve opening degree set in the signal pulse generator 51 by the in-station independent operation command or the turbine stop command 41 is adjusted during the in-station independent operation or when the turbine is stopped. By replacing with the output value of the control calculator 11-2 of the total 11, it is possible to set the optimum control valve opening of the grand steam relief control valve 7 and the auxiliary steam supply control valve 5 in advance. Since the pressure of the turbine gland steam header 3 is adjusted by the signal of 11, the constant pressure control is possible even during the islanding operation alone or when the turbine is stopped.

As described above, according to the present embodiment, the turbine gland steam pressure control, that is, the preceding opening degree setting by the in-house single operation command or the turbine stop command, allows the ground steam pressure to be controlled even when the in-house single operation or the turbine is stopped. It will prevent the decrease and protect the power plant shutdown.

[0039]

As described above, according to the present invention,
Turbine gland steam pressure can be protected from stopping significantly even during in-house operation or a sudden load change that causes large fluctuations in turbine gland steam pressure. Stable control of the power plant enables stable power plant operation.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a fourth embodiment of the present invention.

FIG. 5 is a configuration diagram of a conventional turbine gland steam pressure control device.

[Explanation of symbols]

1 ... High pressure turbine gland, 2 ... Low pressure turbine gland, 3 ... Turbine gland steam header, 4 ... Auxiliary steam supply line, 5 ... Auxiliary steam supply control valve, 6 ... Escape line,
7 ... Grand steam release control valve, 8 ... Turbine ground main steam line, 9 ... Turbine ground main steam control valve, 10
... Pressure detector, 11 ... Controller, 11-1 ... Constant pressure setter, 11-2 ... Control calculator, 12 ... Pressure detector, 13 ... Controller, 21 ... Turbine load signal, 22 ... Advance opening calculation Unit, 23 ... Leading opening command, 24 ... Adder, 31 ... Pressure detector, 32 ... Turbine inlet steam pressure signal, 33 ... Leading opening calculator, 34 ... Leading opening signal, 35 ... Adder, 41 ...
Turbine stop command, 42 ... Leading opening setting device, 43 ... Change rate limiting device, 44 ... High price priority device, 45 ... Leading opening signal, 4
6 ... Subtractor, 50 ... Control valve opening command, 51 ... Signal pulse generator, 52 ... Leading opening setting signal, 53 ... Temporary signal replacement device.

Claims (4)

[Claims] 1. An auxiliary steam supply control valve and a gland steam relief control valve for securing a steam turbine gland pressure, a pressure detector for detecting a turbine gland steam pressure, and a pressure regulator for keeping the gland steam constant. In a turbine gland steam pressure control device configured to open and close both control valves by a signal from the pressure controller,
When the load changes due to the output of the signal adder, it is provided with a preceding opening calculator that makes a preceding shift to the optimum opening according to the turbine load signal, and a signal adder that adds the controller output and the preceding opening calculator output. Turbine gland steam pressure control device, which controls so as to prevent fluctuation of turbine gland steam pressure. 2. The optimum opening preceding opening calculation signal of the control valve,
It is calculated from the turbine inlet steam pressure by the preceding opening calculator, and by adding the controller output and the preceding opening calculation output by the signal adder, it is possible to control so as to prevent fluctuations in the turbine ground steam pressure when the load changes. The turbine gland steam pressure control device according to claim 1, which is characterized in that. 3. When shifting to the in-house independent operation, the controller output and the preceding opening calculation output are added by the signal adder by the preceding opening calculator in response to the instruction to shift to the in-house independent operation and the turbine stop command. The turbine gland steam pressure control device according to claim 1, wherein the turbine gland steam pressure control device is controlled so as to prevent fluctuations in the turbine gland steam pressure when the turbine is stopped. 4. The turbine ground steam pressure according to claim 3, wherein the preceding signal is temporarily replaced with the output value of the controller, and then the temporary signal replacer starts the adjusting signal from the value after replacement. Control device.