JP2006233797A - Steam turbine controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steam turbine controller capable of opening and closing a steam valve quickly and transmitting a command signal accurately and securely. <P>SOLUTION: This steam turbine controller is provided with a mechanical-hydraulic control mechanism part for switching a mechanical signal to a pressure oil signal when controlling opening and closing of the steam valve 1. This steam turbine controller is provided with a control system 2 for start operation for supplying pressure oil to the steam valve 1 and a control system 3 for load operation and is provided with a switching device 4 for switching these two control systems freely. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a steam turbine control device, and more particularly to a steam turbine control device that further accelerates responsiveness to a start command of a main steam stop valve provided at an inlet of a steam turbine.

  In steam turbine plants applied to power plants such as thermal power plants and nuclear power plants, recently, steam turbine control devices are required to have even faster responsiveness based on start-up commands. There is a valve.

  This main steam stop valve has a main valve and a bypass valve (sub valve), and when starting, first opens the bypass valve to control the flow rate of steam supplied from a steam generator such as a boiler to the steam turbine, When a predetermined load is reached, the main valve is opened, and when an accident occurs in the system or the like, it is an ON-OFF type valve that rapidly closes the main valve and the bypass valve based on a trip command.

  As shown in FIG. 3, for example, a thermal power plant incorporating a main steam stop valve having such a function includes a boiler 101, a main steam stop valve 102 having a bypass valve (sub valve) 102b built in the main valve 102a, When the main steam generated from the boiler 101 is supplied to the high pressure turbine 104, the steam control valve 103, the high pressure turbine 104 axially coupled to each other, the intermediate pressure turbine 105, the low pressure turbine 106, and the generator 107 are provided. The opening degree of the steam control valve 103 is adjusted by a control signal from the speed device 109.

  The steam whose flow rate is controlled by adjusting the valve opening degree of the steam control valve 103 performs expansion work in the high-pressure turbine 104 and generates power (rotational torque). The turbine exhaust, which has finished the expansion work in the high-pressure turbine 104, is again heated to high temperature and pressure in the reheater 108 and supplied to the intermediate-pressure turbine 105 as reheated steam for expansion work. Further, the low-pressure turbine 106 performs expansion work. Then, the generator 107 is driven by the power generated at that time.

  On the other hand, the main steam stop valve 102 includes a bypass valve drive unit 110 that opens and closes the bypass valve 102b, a motor 111 that drives the bypass valve drive unit 110, and a turbine activation control calculation unit 112 that gives a command signal to the motor 111. The motor 111 is rotationally driven by a pulse-like signal given from the turbine activation control calculation unit 112, the bypass valve driving unit 110 is driven by this rotational driving force, and the bypass valve 102b is controlled to open and close. The main steam stop valve 102 is provided in a plurality (usually two or four), and when each valve is provided with a main valve and a bypass valve, the number of bypass valves may be half. One of them is extracted as a representative.

  The turbine activation control calculation unit 112 includes a control command unit 113, an adder / subtractor 114, and a thyristor amplifier 115, a bypass valve lift signal (position signal) from the bypass valve position detector 117, and a rotation provided at the shaft end of the generator 107. The speed signal (rotation speed signal) from the number detector 116 and the command signal from the control command unit 113 are calculated by the adder / subtractor 114, the calculation signal is amplified by the thyristor amplifier 115, and the bypass valve drive unit is converted into a pulse signal. 110 is provided to the motor 111.

  Further, as shown in FIG. 5, the control command unit 113 is connected to a speed setter push button 118, and, for example, a love check rotation speed, a low-speed heat soak rotation speed, a high-speed heat soak rotation speed, a rated operation speed, etc. are set in advance. A speed setting device 120 for outputting a speed signal, a speed increasing rate setting device push button 119, and a speed increasing rate setting device 121 for increasing the speed signal from the speed setting device at a predetermined speed increasing rate; A startup characteristic circuit 122 that calculates a speed increase command value from the speed ratio setting device 121 and calculates the turbine rotational speed with respect to the bypass valve opening is provided, and the actual speed signal, bypass valve lift ( Position) signal is added and subtracted by the adder / subtractor 114, and the calculated signal is sent to the main steam stop valve 10 via the thyristor amplifier and the motor 111 of the bypass valve drive unit 110. It is performed valve control given to the bypass valve 102b.

  Further, as shown in FIG. 4, the bypass valve drive unit 110 includes an all-round injection operation mechanism unit 124 including a piston 124 a that moves forward and backward by the driving force of the motor 111 or the operation handle 123 at the time of activation. The all-round injection operation mechanism 124 is connected to the main steam stop valve 102 via a lever 125, a floating lever 126, a relay valve 127, a pilot valve 128, and a restoration stopper 129.

  The main steam stop valve 102 accommodates a main valve 102a containing a bypass valve (sub valve) 102b in a valve casing 130, and is connected via a valve rod 131 and a joint 132 for opening and closing the bypass valve 102b and the main valve 102a. And a disc dump valve 135 that discharges the pressure oil in the oil cylinder 134 to the outside in the event of an emergency such as a trip.

  In the main steam stop valve 102 having such a configuration, when the motor 111 is driven by a start command from the turbine start control calculation unit 112 or the operation handle 123 is driven by an operator, The injection operation mechanism 124 moves the piston 124 forward and backward, pulls the lever 125 from the position of the solid line to the position of the one-dot chain line in the counterclockwise direction, and accordingly moves the floating lever 126 in the direction of the arrow E to thereby move the pilot valve. While the 128 spools are moved downward, they are brought into contact with the restoring stopper 129.

  When the floating lever 126 comes into contact with the restoration stopper 129, the control oil from the relay valve 127 is supplied to the oil cylinder 134 via the pilot valve 128 and the disk dump valve 135 to press the oil cylinder piston 133, and this pressing force Is provided to the bypass valve 102b via the valve rod 131, and the bypass valve 102b is opened. The main steam stop valve 102 opens and closes the bypass valve 102b until the outlet-side steam pressure (steam chest pressure) reaches a predetermined steam pressure, and controls the flow rate of steam passing through the main steam stop valve 102.

  In addition, when an accident occurs in the system during operation and a trip command is issued, the main steam stop valve 102 is supplied with emergency oil and moves the piston of the trip valve 136. With this movement, the latch 137 is released. The lever 125 is returned to the position of the solid line, and the spool of the pilot valve 128 is further moved to close the port, and the emergency oil is supplied to the relay valve 127 to close the port, and the relay valve 127 passes through the pilot valve 128. The supply of control oil to the oil cylinder 134 is turned off.

  Further, the main steam stop valve 102 supplies emergency oil to the oil cylinder 134, moves the disc dump valve 135 downward, and discharges the pressure oil accumulated in the oil cylinder 134 as drainage from the inside of the vessel. Accordingly, the oil cylinder piston 133 is lowered and the bypass valve 102b and the main valve 102a are closed.

  In addition, the main steam stop valve 102 is provided with a test device 138 in order to confirm during operation whether the bypass valve 102b and the valve rod 131 that drives the main valve 102a are stuck by impure solids such as oxide scale. I have. This test device 138 is a spool equipped with an electromagnetic valve, moves the spool of the relay valve 127 with an air signal from the spool, closes the port, and controls oil from the relay valve 127 to the oil cylinder 134 via the pilot valve 128. The valve rod 131 is confirmed to move downward.

The opening and closing of the main steam stop valve during an emergency is also disclosed in, for example, Japanese Patent Laid-Open No. 10-131710 (Patent Document 1).
Japanese Patent Laid-Open No. 10-131710

  In the conventional steam turbine control device shown in FIGS. 3 to 5, when the bypass valve and the main valve of the main steam stop valve are opened and closed, the pressure oil is supplied to and discharged from the spool in response to the response of the lever or the floating lever. Since it is a so-called machine-hydraulic control device, it has several problems.

  That is, as described above, the steam turbine performs control for fine monitoring such as love check, low-speed heat soak, high-speed heat soak, etc. to ensure stable operation during start-up operation, but the signal transmission path is a lever, floating lever, etc. As a result of long-term use, the mechanical type of this type has a concern that a loose portion or a non-operating portion such as a gap is formed in the connection portion, signal transmission is delayed, and it is difficult to ensure the above stable operation.

  Further, since the steam turbine is the above-described mechanical-hydraulic control device, it has a signal delay responsiveness, requires time for settling between the predetermined target rotational speed and the actual rotational speed, and the startup operation time. The system parallel load operation accompanying the prolongation of the system is delayed, and there has been a problem that more energy such as fuel is consumed during this period.

  For this reason, it has been desired to realize a control device that transmits a command signal earlier and more reliably to a steam turbine and opens and closes a steam valve such as a main steam stop valve earlier.

  The present invention has been made based on such circumstances, and enables a steam valve such as a main steam stop valve to be opened and closed more quickly, and allows a command signal to be transmitted more accurately and reliably. An object of the present invention is to provide a steam turbine control device.

  In order to achieve the above-mentioned object, a steam turbine control device according to the present invention is a mechanical-hydraulic control that switches a mechanical signal to a pressure oil signal when controlling opening and closing of a steam valve, as described in claim 1. In the steam turbine control device provided with a mechanism, a start-up operation control system and a load operation control system that supply pressure oil to the steam valve are provided, and a switching device that freely switches between these two control systems is provided. Is.

  Further, in order to achieve the above-described object, the steam turbine control device according to the present invention provides a start-up operation control system in which an electric oil for switching an electric control command signal to a pressure oil control signal is provided. A conversion device is provided.

  In order to achieve the above-mentioned object, the steam turbine control device according to the present invention is configured such that the load operation control system is connected to the steam valve from the switching valve of the switching device via the pilot valve. The pressure oil is directly supplied to the oil cylinder that houses the oil cylinder piston that drives the cylinder.

  In order to achieve the above object, the steam turbine control device according to the present invention includes a switching solenoid valve that is responsive to a command signal, and the switching solenoid valve. A switching valve that switches the pressure oil from one of the starting operation control system and the load operation control system to the pressure oil of the other system and supplies it to the oil cylinder of the steam valve. It is equipped with.

  In order to achieve the above-mentioned object, the steam turbine control device according to the present invention is characterized in that the steam valve is a main steam stop valve.

  The steam turbine control device according to the present invention is provided with two control systems, that is, a start-up operation control system and a load operation control system, when opening and closing a steam valve such as a main steam stop valve, and the two control systems can be freely set. On the other hand, an electro-oil conversion device that switches the electrical signal to pressure oil is provided in the start-up operation control system, so that the steam valve can be opened and closed more quickly and more accurately and more reliably. The command signal can be transmitted, and the steam turbine can be operated stably for a long time.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a steam turbine control device according to the present invention will be described with reference to the drawings and reference numerals attached to the drawings.

  FIG. 1 is a schematic control system diagram showing an embodiment of a steam turbine control device according to the present invention.

  In addition, although the steam turbine control apparatus which concerns on this invention makes the main steam stop valve applicable as an example, it is not restricted to this example, Many kinds of steam valves used for steam turbines, such as a reheat steam stop valve, Also applies.

  Among the steam valves to which the steam turbine control apparatus according to the present embodiment is applied, the illustrated main steam stop valve 1 includes a start-up operation control system 2 used during start-up operation and a load operation used during load operation. And a switching device 4 that can freely switch between both control systems 2 and 3.

  The start-up operation control system 2 incorporates an electro-hydraulic control device that converts an electrical signal into pressure oil.

  On the other hand, the main steam stop valve 1 accommodates a main valve 7 containing a bypass valve (sub valve) 6 in a valve casing 5, and via a valve rod 8 and a joint 9 for opening and closing the bypass valve 6 and the main valve 7. And a disk dump valve 12 for discharging the pressure oil in the oil cylinder 11 to the outside as a drain in the event of an emergency such as a trip.

  In addition, the start-up control system 2 connected to the main steam stop valve 1 includes an oil filter 13 that can be freely switched by clogging or the like in order along the flow of control oil, and command electric power from the turbine start-up control calculation unit 14. An electro-oil conversion device 15 that switches the signal to pressure oil is provided.

  This electro-oil conversion device 15 is a combination of a conversion circuit 15a that converts an electrical signal into a hydraulic signal and a spool 15b, and skillfully uses faster transmission and reliable transmission by the electrical signal. is there.

  The start-up control system 2 includes a relay valve 16 that supplies control oil from the spool 15b of the electro-oil conversion device 15 to the oil cylinder 11 of the main steam stop valve 1 via the switching device 4 and the pilot valve 18. ing.

  The switching device 4 is switched from the start-up operation control system 2 to the load operation control system 3 by the switching electromagnetic valve 17a that is operated by an electrical command signal from the turbine start-up control calculation unit 14 and the driving force of the switching electromagnetic valve 17a. And a switching valve 17b for switching.

  The pilot valve 18 is provided with a test electromagnetic valve 25 so that it can be checked whether or not the valve stem 8 of the main steam stop valve 1 is stuck even during operation.

  In addition, the load operation control system 3 directly supplies the control oil to the switching valve 17b and also to the oil cylinder 11 through the pilot valve 18 with the help of the main steam stop valve 1 being an ON-OFF type. It is configured to supply.

  On the other hand, as shown in FIG. 2, the turbine activation control calculation unit 14 that gives an electric command signal to the electro-oil conversion device 15 and the switching electromagnetic valve 17 a is connected to a speed setting push button 19, for example, a love check rotation speed, The speed setter 20 is connected to a speed setter 20 for outputting a preset speed (rotational speed) signal such as a low-speed heat soak rotational speed, a high-speed heat soak rotational speed, a rated rotational speed, and the like, and a speed increase rate setting push button 21. The speed increase rate setting unit 22 for increasing the speed signal from the speed increase rate at a predetermined speed increase rate, and the addition / subtraction for matching the actual speed of the turbine (turbine actual rotation speed) with the speed increase command signal from the speed increase rate setting unit 22 And a start-up settling rate calculator 24 for calculating a settling rate for start-up based on a calculation signal of the adder / subtractor 23, and a calculation signal from the start-up settling rate set 24 is sent to the electro-oil conversion device 15. It has become to obtain configuration.

  In the steam turbine control device having such a configuration, when a start command is given from the turbine start control calculation unit 14 to the electric oil conversion device 15, the control oil from the oil filter 13 passes through the spool 15 b and the relay valve 16. It is supplied to the switching valve 17b of the switching device 4. At this time, the switching valve 17b has not yet switched the spool.

  The control oil supplied from the relay valve 16 to the switching valve 17b is supplied to the oil cylinder 11 from here through the pilot valve 18 and the disk dump valve 12, presses the oil cylinder piston 10, drives the valve stem 8, The bypass valve 6 is opened, and the flow rate of the main steam supplied from the main steam inlet to the steam control valve (not shown) is controlled.

  Although not shown, all of the other main steam stop valves perform so-called all-round injection operation in which the bypass steam is opened and main steam flows.

  After the bypass valve 6 is opened by the all-round injection operation, when the pressure of the steam chest on the outlet side of the main steam stop valve 1 reaches a predetermined pressure, the main steam stop valve 1 opens the main valve 7 fully.

  When the start-up operation is completed and the load operation of the steam turbine is started, the steam turbine control device from the start-up operation control system 2 that has supplied control oil to the oil cylinder 11 of the main steam stop valve 1 until now, Switch to the control system 3 for load operation.

  That is, the switching electromagnetic valve 17a of the switching device 4 receives a switching command from the turbine start control calculation unit 14, moves the spool, and transfers a part of the control oil supplied from the pilot valve 18 to the oil cylinder 11 to the spool. It supplies to the switching valve 17b through a port.

  The switching valve 17b moves the spool, cuts off the supply of control oil from the relay valve 16, and supplies the control oil from the piping of the load operation control system 3 to the spool.

  The control oil supplied from the piping of the load operation control system 3 to the spool of the switching valve 17b is supplied to the oil cylinder 11 via the pilot valve 18 to maintain the pressing force to the oil cylinder piston 10 and maintain the main valve 7. The fully open state is maintained.

  Thus, in this embodiment, when the bypass valve 6 and the main valve 7 of the main steam stop valve 1 are opened, the start control system 2 for supplying control oil to the oil cylinder 11 of the main steam stop valve 1 and the load While providing two control systems with the operation control system 3 and providing a switching device 4 that can freely switch between the two control systems, an electric control command from the turbine start control computing unit 14 is provided to the start control system 2. Since the electro-oil conversion device 15 for converting into pressure oil is provided, the open / close response of the bypass valve 6 and the main valve 7 of the main steam stop valve 1 becomes faster, and the transmission of the open / close signal is more reliable and accurate. Therefore, it is possible to operate with high accuracy and stability when the steam turbine is started, and by switching to the load operation control system during normal operation, even if the electro-hydraulic converter or the start-up control system fails, the unit It can perform a reliable operation, which can continuously operate the turbine without stopping the.

1 is a schematic control system diagram showing an embodiment of a steam turbine control device according to the present invention. The block diagram which shows the turbine starting control calculating part applied to the steam turbine control apparatus which concerns on this invention. The conceptual diagram which shows a general thermal power plant. The conceptual diagram which shows the conventional mechanical-hydraulic control apparatus applied when opening and closing the bypass valve and main valve of a main steam stop valve. The block diagram which shows the turbine starting control calculating part applied to the conventional mechanical-hydraulic control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main steam stop valve 2 Control system for start-up operation 3 Control system for load operation 4 Switching device 5 Valve casing 6 Bypass valve 7 Main valve 8 Valve rod 9 Joint 10 Oil cylinder piston 11 Oil cylinder 12 Disc dump valve 13 Oil filter 14 Turbine Start-up control calculation unit 15 Electro-oil conversion device 15a Conversion circuit 15b Spool 16 Relay valve 17a Switching solenoid valve 17b Switching valve 18 Pilot valve 19 Speed setting push button 20 Speed setter 21 Speed increase rate setting push button 22 Speed increase rate setter 23 Addition / subtraction Controller 24 Start-up regulator 25 Test solenoid valve 101 Boiler 102 Main steam stop valve 102a Main valve 102b Bypass valve (sub valve)
103 Steam Control Valve 104 High Pressure Turbine 105 Medium Pressure Turbine 106 Low Pressure Turbine 107 Generator 108 Reheater 109 Governor 110 Bypass Valve Drive Unit 111 Motor 112 Turbine Start Control Operation Unit 113 Control Command Unit 114 Adder / Subtractor 115 Thyristor Amplifier 116 Rotation Number Detection Device 117 bypass valve position detector 118 speed setting device push button 119 acceleration rate setting device push button 120 speed setting device 121 acceleration rate setting device 122 start characteristic circuit 123 operation handle 124 all-round injection mechanism 124a piston 125 lever 126 floating lever 127 relay valve 128 Pilot valve 129 Restoration stopper 130 Valve casing 131 Valve rod 132 Joint 133 Oil cylinder piston 134 Oil cylinder 135 Disc dump valve 136 Trip valve 137 Latch 138 Test device

Claims (5)

In a steam turbine control device having a mechanical-hydraulic control mechanism that switches a mechanical signal to a pressure oil signal when opening and closing the steam valve, a control system for start-up operation for supplying pressure oil to the steam valve and load operation And a control device for switching between these two control systems. The steam turbine control device according to claim 1, wherein the start-up operation control system includes an electro-oil conversion device that switches an electric control command signal to a pressure oil control signal. The load operation control system is configured to supply pressure oil directly to an oil cylinder that houses an oil cylinder piston that drives a steam valve from a switching valve of a switching device via a pilot valve. The steam turbine control device according to 1. The switching device responds to the switching solenoid valve that responds to the command signal and the driving force of the switching solenoid valve, and supplies pressure oil from either of the start-up operation control system and the load operation control system. The steam turbine control device according to claim 1, further comprising a switching valve that switches to the pressure oil of the other system and supplies the pressure oil to the oil cylinder of the steam valve. The steam turbine control device according to claim 1, wherein the steam valve is a main steam stop valve.

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