SU1163010A1 - System for controlling turbine heat duty - Google Patents

Description

The invention relates to a power system and can be used in the automation of turbines with steam extraction.

Closest to the invention is a system for regulating the heat load of the turbine, containing a control valve installed on the steam line between the steam extraction chamber and the heat consumer and equipped with a drive, regulator of the consumed heat with outputs “More '·' and“ Less ” connected to the actuator of the control valve, and the controller * available heat load with outputs "More" and "Less" WITH · 15

A disadvantage of the known system is the somewhat lower reliability of the turbine due to insufficient regulation quality — increased overshoot and increased regulation time 20.

The purpose of the invention is to improve the reliability of the turbine by improving the quality of regulation.

To achieve this goal, 25 a turbine heat load control system containing a control valve installed on the steam line between the steam extraction chamber and the heat consumer and equipped with a 30 actuator, a heat demand regulator with more and less outputs connected to the control valve actuator, and regulator of available heat load with outlets & "More" and "Less", equipped with a shock-free impact unit with switching contacts at its output, outputs "More" and "Less" regulator available the heat load is connected to the actuator of the control valve, and the switching contacts are inserted into the actuator line "More" of both regulators to this actuator. · 45

The shock-free unit can be made in the form of logical elements OR and BANKS and a relay element connected to their output, while the “Less” terminals of both regulators are connected to the inputs of the unit.

In order to increase reliability when there is a reserve steam source with a regulating valve and a drive, the system is equipped with a final switch of the reserve steam actuator valve and a regulator of the reserve heat consumption with outlets

^ 'More' and 'Less', connected to the backup-valve control valve actuator, the impact-free impact block is made as an OR or relay element, the Less-less output of the controller of the available thermal load and the limit switch output are connected to the block inputs entered in the line connecting the "Less" output of the heat consumption regulator to the control valve actuator and the "More" output of the reserve heat consumption regulator to the backup steam valve actuator.

The invention provides, together with the ability to stabilize the parameter set by the heat consumer when the turbine heat load is less than the limit and with the heat load limited by the turbine when it is increased to the limit value, high-quality control in the heat load limit mode of the turbine by eliminating the negative influence of the signal in this mode according to the parameter determined by the heat consumer, on the formation of the regulatory action.

If the system is equipped with a reserve source of steam, while limiting the heat load of the turbine, the parameter specified by the heat consumer is stabilized by switching on the reserve source of steam.

This is explained by the fact that the proposed system is built with a variable structure of regulatory actions, i.e. The outputs of the consumed heat regulators and the available heat load are connected to the control valve actuator depending on the system operation mode: in the stabilization mode of the parameter set by the heat consumer, the heat demand regulator is connected to the control valve, and the available heat load regulator is connected to the heat load control mode. .

The restructuring of the system, i.e. determination of the mode in which the regulation system should operate, and the connection of the output of the regulator corresponding to the selected mode, to the control drive

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valve is performed by the shockless block. A necessary and sufficient condition by which the control system is put into the mode of limiting the heat load of the turbine is an increase in the heat load of the turbine to the limit value, which is judged by the appearance of a signal at the "Less" output of the controller of the available heat load. For the 10 reverse transfer of the regulation system to the stabilization mode of the parameter set by the heat consumer, lowering the turbine heat load to the limiting value by the value of the 15 mode parameter (as evidenced by the appearance of a signal at the "More" output of the available heat load regulator) is necessary but not sufficient . In this case, 20 an additional condition is imposed, according to which the value of the parameter specified by the heat sink must be equal to the specified value, which can be judged by the absence of signals at the outputs of the heat consumption controller.

When the heat load of the turbine is less than the limiting value, there is some reserve for the heat load of the turbine. If you switch the regulation system from the turbine heat load limiting mode to the stabilization mode of the parameter set by the heat consumer, only 35 based on the fact that this reserve is available for the heat load, the turbine, without estimating its value, the actions of the heat consumption regulator aimed at stabilizing the parameter set by heat - 40 consumers, and accompanied by an increase in the heat load of the turbine, can lead to a re-increase in the heat load of the turbine to pre ~. individual value, if the available EA-45 pass on the heat load of the turbine is insufficient. Such a phenomenon, which occurs when the structure of regulators changes, is called a “blow”. To prevent this, the control system 50 at the command of the shock-free unit continues to remain in the thermal-load limiting mode, despite the fact that the thermal load of the turbine is 55 less than the limit. This output _ν "More" regulator available heat load continues to be connected to the actuator of the control valve, and at this output a signal appears, aimed at increasing thermal load of the turbine, i.e. on the implementation of the appeared stock on the turbine heat load. As a result of such actions of the controller of the available heat load, when the heat load of the turbine on his command increases, the parameter specified by the heat consumer approaches the specified value,

And, if the stock on the thermal load of the turbine is sufficient, takes this value.

In this case, the system is switched; in the mode of stabilization of the parameter set by the heat consumer, and in the presence of a source of reserve steam, it is switched off. Since at the same time the regulator of the consumed heat is in a state of balance (there are no signals at its outputs), the switching carried out is unstressed. .

FIG. 1 shows a system for regulating the heat load of a turbine without a source of reserve steam; in fig. 2 - the same, with a source of reserve steam.

The system for regulating the heat load of a turbine without a source of reserve steam (Fig. I) contains a steam turbine 1 with a steam pipe 2 connecting the selection chamber 3 with a heat consumer (not shown). On the steam line 2 there is a control valve 4 with a drive 5 having inputs 6 “Open” and 7 “Close”. Inlet 7 "Close" of the actuator 5 of the control valve 4 is connected to the output 8 "Less" of the regulator 9 of the heat consumed and to the output 10 "Less than" of the regulator 11 of the available thermal load. Output 12 "More" of the regulator 9 of the consumed heat and output 13 "More" of the regulator 11 of the available heat load are connected to input 6 of the "Open" drive 5 via the switching contacts 14 of the block 15 without impact, and outputs 8 and 10 "Less" of these regulators - to the inputs of the block 15, made in the form of a logical element OR 16, a logical element 17 and a relay two-element element 18.

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To the input of the regulator 9 consumed heat connected sensor 19 parameter specified by the heat consumer (for example, steam pressure in the collector production selection ¹ ) and the setter 20. To the input of the regulator 11 available heat load connected sensors 21 and 22 steam pressure to. and after the pre-selection compartment, respectively, characterizing the regime parameter of the turbine - the maximum power of the pre-selection compartment.

Thermal control system. turbine loads with a source of reserve steam 23 (Fig. 2) additionally 15 contains a control valve 24 of reserve steam with a drive 25 having inputs 26 "Open" and 27 "Close" and limit switch 28 and regulator

29 consumed heat reserve 20 steam with outlets 30 "More" and 31 "Less". To the inputs of the regulator 29 is connected to the sensor 19 and the setpoint 32.

The unstressed impact unit 15 is made in the form of a logic element 25 OR 16 and a two-position relay element 18. The inputs of the unit 15 are connected to the output 10 “Less” of the regulator 11 and to the output of the limit switch 28. The switching contacts 30 33 and 34, also connected to the output of the block 15 entered respectively into the line connecting the output 8 "Less" regulator 9 to the input 7 "Close" of the drive 5 and the line connecting the output

30 "More" regulator 29 to the input 26 of the "Open" drive 25.

The control system without a source of reserve steam works as follows. 40

The available thermal load of the turbine is determined by the power of the pre-selection compartment. The signal <about the available thermal load of the turbine is formed at the output of the regulator-45 of the torus 11 of the available thermal load, depending on the pressure ratio to (signal at the output of pressure sensor 21) and after (signal at the output of pressure sensor 22) pre-selection 50 compartment. When the power of the pre-selection compartment is limiting, there are no signals at the outputs of 10 "Less ·" and 13 "More" regulator 11, which corresponds to the maximum load of the turbine. 55

If the power of the pre-selection compartment is less than the limit, the output 11 of the "More" regulator 11 appears

cash informing that the heat load of the turbine is less than the limit. The system operates in the mode of stabilization of the parameter specified by the heat consumer. In this mode, the switching contacts 14 of the non-shock impact unit 15 connect the output 12 of the “More” regulator. 9 heat consumption with input 6 "Open" actuator 5 valve 4. The signals from the sensor 19 of the parameter specified by the heat consumer, and the setting unit 20 is fed to the input of the regulator 9, where they are converted into a sequence of control pulses at the outputs 8 "Less" or 12 "More" the regulator and go to the corresponding inputs 6 "Open" and 7 "Close" of the actuator 5 of valve 4. The control valve 4 moves in the desired direction and supports the parameter set by the thermal consumer.

The regulator 11 of the available heat load in this mode does not participate in the operation, since the signal at its output 13 "More" is disconnected by contacts 14 from valve 5 actuator 4.,

When the turbine heat load increases, the signal that goes to input 7 "Close" of actuator 5 of valve 4 causing its cover and input to element 16 that implements the logical function OR appears at output 10 "Less" of regulator 11 of available heat load. Closing the valve 4 reduces the thermal load of the turbine to the limit value at which the output signal 10 "Less" regulator 11 disappears.

The signal at the input of the element 16 causes. The signal at the output of this element and enters the direct input of the element 17, which implements the logical function BAN, and the input of the relay element 18, which causes it to trigger and switch contacts 14. At the same time, the output 12 "More" regulator 9, the heat consumed is disconnected from the input 6 of the “open” drive 5 of valve 4, and the output 13 “More” of the regulator 11 is connected to this input, i.e. the system goes into the mode of limiting the thermal load of the turbine. In this mode, due to the required cover of the control valve 4, at the command of the regulator 11,

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the deviation of the parameter set by the thermal consumer, from the specified value in the downward direction. At output 8 "Less" regulator 9, the signal is absent, and at output 12 5

There is a “more” of this regulator, but it is disconnected from the actuator 5 of valve 4 by pins 14. The absence of a signal at output 8 “Less” of regulator 9 connected to the YBU input of the BANNER 17, if there is a signal at its direct input, causes a signal at the output of this element and the arrival of this signal at the input of element 16, and 15 also the preservation of this signal in this case, when the signal arriving at the input of the logical element OR 16 from the output 10 "Less" of regulator II disappears, i.e. when heat load is 20 ka turbine takes an acceptable value.

When the cause of the unacceptable increase in the heat load of the turbine and the transition of the re-25 homing system to the heat load limiting mode is removed, the heat load of the turbine becomes lower than the limit, and a signal appears at the output 13 "More" of regulator 11 of the available heat load 30. This signal through the switching contacts 14 is fed to the input 6 of the “Open” of the actuator 5 of the valve 4, causing it to open and thereby maintaining the thermal load of the turbine at the limiting value until the value of the parameter specified by the heat consumption takes the set value value, which is judged either by the fact that there are no signals at outputs 40 and 8 and 12 of regulator 9 or, in order to simplify the system, after the appearance of a signal at output 8 "Less", as it is done in the proposed system. The appearance of a signal at 45 output 8 of the “Less” regulator 9, ₉ connected with the inverse input of element 17, causes the signal at the output of element 17 and the input of element 16 to disappear. So 50 as there is no signal at the other input of this element / turbine thermal load does not exceed the limit value, and there is no signal at the output 10 of the regulator 11}, at the output of the element 55 and 16 and respectively at the input of the element 18 the signal disappears, which causes switching of the contacts 14. At

This control system enters the stabilization mode parameter. specified by the heat consumer; i.e ^; . output 13 “More” of regulator 1] is disconnected from input 6 “Open” of actuator 5 of valve 4, and output 12 “More” of regulator 9 is connected to this input.

Since at the moment of switching at output 8 "Less" of regulator 9 there is a signal covering valve 4, the actions of regulator 9 aimed at stabilizing the parameter of the heat consumer cause only some additional decrease in the heat load of the turbine, i.e. Switching is “non-impact”.

The control system with a source of reserve steam (Fig. 2) works as follows.

The available thermal load of steam extraction from the turbine (for example, from the cold reheat line ^ is determined by the regime parameter of the metal temperature of the secondary superheater of the boiler. If the metal temperature of the secondary superheater of the boiler is below the limit, the output 13 "More" of regulator II gives a signal that the thermal the load of selection from the cold reheat (main selection) is less than the limit. The system operates in the mode of stabilization of the parameter set by the heat consumer from the main selection, cut A disconnected steam source (for example, hot reheat extraction) is disconnected. In this mode, the switching contacts 14 connect the output 12 “More” of the regulator 9 to the input 6 “Open” of the drive 5 of the valve 4. The contacts 33 connect the output 8 “Less” of the regulator 9 with input 7 "Close" of drive 5. Thus, control valve 4 supports the parameter set by the thermal consumer. Regulators 11 of the available heat load and regulators 29 of the consumed heat of the backup source are not involved in the operation, since the "More" signal on their outputs 13 and 30 respectively but it is turned off by switching contacts 14 and 34. Limit switch 28 is off, there is no signal at its output. In this mode, the system works similarly to a system without a backup source.

With an increase in the heat load of the main selection above the permissible

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the values at output 10 “Less” of the regulator 11, a signal appears, which is fed to the input 7 “Close” of the actuator 5 of valve 4, causing it to be covered. The signal also enters the input element 16, which implements a logical. OR function. Closing the valve 4 reduces the thermal load of the main turbine take-off to the limit value at which the signal at output 10 “Less” of the regulator 11 disappears. The signal at the input of the element 16 causes the appearance of a signal at the output of this element, which is fed to the input of the relay element 18, which causes its triggering and switching contacts. At the same time, the output 12 “More” of the regulator 9 of the consumed heat by the switching contacts 14 is disconnected from the input 6 “Open”, and the output 13 “More” of the regulator 11 is connected to this input of the drive 5 ₍ valve 4.

Output 8 "Less" of regulator 9 is disconnected by contacts 33 from input 7 '' Close "of actuator 5 of valve 4, and output 30" More "of regulator 29 of consumed heat of the backup source by contacts 34 is connected to input 26 of" Open "Drive 25 of valve 24 of backup pair. Thus, in this mode, due to the need to cover the valve 4 at the command of the regulator 11, the regulator command 29 opens the reserve steam valve 24 to maintain the parameter set by the thermal consumer. When connecting the output 30 "More" of the regulator · 29 to the input 26 "Open The limit switch 28 is turned on. A signal appears at the output of the limit switch 28 and is fed to the input of the element 16 of the block 15. The presence of a signal from the limit switch 28 at the input of the element 16 causes the signal to appear at the output of this element and ensures that the signal remains at the input of the relay. element 18 and in the case when the signal arriving at the input of the element OR 16 from the output 10 “Less” of the regulator 11 disappears, i.e. when the heat load of the main selection takes on an acceptable value.

Thus, when turning on the source of the reserve steam, the controller 11 maintains the heat load of the main selection at the limiting value,

and the parameter set by the heat consumer is maintained by the controller 29 of the consumed heat of the source

5 23 reserve pair.

When the consumer’s heat load decreases, at output 31 "Less" of regulator 29, a signal appears that goes to input 27 "Close" priv | | yes 25 of valve 24, and the signal from output 13 "More" regulator 11 arrives at input 6 "Open" actuator 5 valve 4, maintains the heat load of the main selection at the limiting

. value of. If the parameter set by the thermal consumer is provided from the main selection of the turbine, the valve 24 of the backup steam is completely closed by the signal from output 31 "Less",

/ 0 which leads to the disconnection of the limit switch 28 and the disappearance of the signal at its output.

The disappearance of the signal at the output Ko ⁴ gnechnogoo switch 28 is used

75 the signal at the input of the element 16. Since there is no signal at the other input of this element (the thermal load of the main turbine selection does not exceed the limit value, and

30 output 10 "Less" regulator 11 no signal), at the output of the element 16 the signal disappears, which causes switching contacts. In this case, the regulatory system enters the mode

35 of stabilization of the parameter set by the heat consumer from the main extraction, i.e., output 13 “More” of regulator 11 is disconnected from input 6 of actuator 5 of valve 4, and output 30 “More than 40” of regulator 29 is disconnected from

the input 26 of the actuator 25 of the valve 24, and the output 12 "More" of the regulator 9 is connected to the input 6 of the actuator $ valve 4. Since at the time of switching

There is a signal to close valve 24 at outlet 31 "Less" of regulator 29, and therefore output 8 of "Less" of regulator 9 also has a signal, when control is sent to regulator 9 to maintain the parameter set by the heat sink, the switch is "unstressed ".

The proposed system for regulating the heat load of the turbine has the following advantages compared with the known one:

reliability of the turbine is increased by improving the quality of the regulation55

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in the mode of limiting the thermal load of the turbine by eliminating this mode is from the process of forming the regulatory effect of the signal about the parameter specified by the heat consumer;

simplifies the operation of the regulatory system by using a three-position thermal load as the regulator of the available 10

or pulse controller instead of analog.

In addition, the system for regulating the heat load of a turbine with a source of reserve steam is more economical due to the automation of switching on and off the source of reserve steam, which ensures maximum use of a more economical primary steam source.

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Claims (3)

1. SYSTEM OF REGULATION OF THERMAL LOADING OF THE TURBINE, containing a control valve installed on the steam line between the steam extraction chamber and the heat consumer and driven, a regulator of heat consumption with more / and less outlets connected to the control valve actuator • available heat load with “More” and “Less” outputs, which is due to the fact that, in order to increase the reliability of the turbine by improving the quality of regulation, the system is equipped with a shock-free impact unit with switching contacts at its output, the outputs "More" and "Less" of the controller of the available thermal load are connected to the actuator of the control valve, moreover, in the connection line of the outputs "More" of both regulators switching contacts have been entered to this drive. 2. The system of clause 1, distinguishes ayu shch a ή with i <that the unit is unstressed; The main influence is made in the form of logical elements OR and BANNER and a relay element connected to their outputs, while the “Less” outputs of both regulators are connected to the block inputs. 3. System pop. I, characterized in that, in order to improve reliability in the presence of a reserve steam source with a regulating valve and a drive, it is additionally equipped with a limit switch of the backup steam valve actuator and a regulator of the reserve steam consumed heat with more and less outputs, connected to the actuator of the control valve of the reserve steam, the block of impact-free impact is made in the form of an OR logic element and a relay element; The switching contacts are additionally introduced in the lines connecting the "Less" output of the heat consumption regulator to the control valve actuator and the "More" output of the reserve heat consumption regulator to the backup valve actuator, steam. BEFORE ABOUT > one 1163010 2