JPH0299702A - Control device for turbine bypass valve - Google Patents

Abstract

PURPOSE:To enable the opening of a bypass valve to be adjusted manually as needed, by providing, a means for subjecting a bypass valve operating system to forced-reset from its state in an emergency time to that in a normal time based on a reset command given from an exterior. CONSTITUTION:When a push button switch for forced-resetting is pushed to be operated, a reset command signal 16 is generated, so that a flip flop 11d is reset through an OR circuit 11e. It is thus possible to switch an operating system selector 11b from an emergency time bypass valve operating system to a normal time bypass valve operating system. When an auto-manual switch 11a is switched in a manual mode in the operation of the normal time bypass valve operating system, the opening of a turbine bypass valve can be adjusted freely. It is thus possible to correct suitably the opening of the turbine bypass valve in the state when automatic switching from the normal time bypass valve operating system to the emergency time bypass valve operating system is achieved in response to a turbine trip.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention 1 (Industrial Application Field) The present invention relates to a control device for a turbine bypass valve applied to steam turbine equipment and the like.

(Prior Art) FIG. 2 is a piping system diagram showing an example of steam turbine equipment to which the present invention is applied.

As shown in the figure, steam from a boiler (not shown) is temporarily stored in a steam reservoir 1, and then passes through a turbine 2 to reach a condensation facility 3 through a main flow path 4 and a main flow path 4, bypassing the turbine 2 and passing through the condensation facility. It is branched into a pipe bus flow path 5 which leads to 3.

The main flow path 4 is provided with a turbine inlet steam flow meter 5 and a steam control valve 7, respectively.

Further, the bypass passage 5 is provided with a turbine bypass flow meter 8 and a turbine bypass valve 9, respectively.

Note that 10 in the figure is a steam reservoir pressure system.

As is well known, in this type of steam turbine equipment, if the turbine 2 is tripped due to some abnormality, the shutoff valve built in the inlet side of the turbine 2 will be shut off, and if this continues, large pressure fluctuations will occur in the steam reservoir 1. , adversely affecting other steam utilization equipment, etc.

Therefore, in conventional steam turbine equipment of this type, when the turbine 2 trips and the inlet shutoff valve is shut off,
Pressure fluctuations are absorbed by turning on the turbine bypass valve 8 in proportion to the steam flow rate that had previously flowed through the main flow path 4.

Control of the turbine bypass valve 8 in such an emergency is performed using a control device including a switching device 11 and a loop controller 12.

This control device includes a normal bypass valve operation system and an emergency bypass valve operation system.

The normal bypass valve operation system is further provided with an automatic mode and a manual mode, and the turbine bypass valve 9 is controlled using a loop controller 12 that performs PI calculation.

That is, the loop controller 12 detects the bypass flow rate via the turbine bypass flow meter 8 and generates a bypass valve operation output using a closed loop so that the bypass flow rate becomes the set flow gutter S■. The output passes directly through the switching device 11 and is applied to the turbine bypass valve 9.

On the other hand, in the case of manual mode, the loop controller 12
The bypass valve operating output from the switching device 11 is disconnected, and the operating output generated from the manual operator built in the switching device 11 is directly applied to the turbine bypass valve 9, whereby the opening degree of the turbine bypass valve 9 can be controlled by manual operation. Can be set arbitrarily.

On the other hand, in the emergency bypass valve operation system, the switching device 1 mainly performs its function.

That is, in the switching device 1, when the operation as an emergency bypass valve operation system is started, the turbine inlet steam flow meter 6
Turbine inlet flow mk immediately before trip detected via
: Based on this, a flow rate-valve opening calculation is executed, a bypass valve operation output corresponding to the corresponding valve opening obtained thereby is generated in an open loop, and this is applied to the turbine bypass valve 9.

As a result, the turbine bypass valve 9 is instantaneously opened in proportion to the amount of steam 1 that was flowing through the main flow path 4 immediately before the trip, thereby absorbing the fluctuation in flow rate due to the turbine trip.

Thereafter, the value of the turbine bypass valve operation output output from the switching device 11 is gradually reduced as the system stabilizes.
When it matches the operation output value from the normal bypass valve operating system, that is, from the loop controller 12, the normal bypass valve operating system is automatically returned to.

When a turbine trip occurs, the normal bypass valve operating system is automatically switched to the emergency bypass valve operating system.

(Problem to be Solved by the Invention) However, in such a conventional turbine bypass valve 1illD device, - after the normal bypass valve operating system is switched to the emergency bypass valve operating system, Then, until the bypass valve operation output value generated from the emergency bypass valve operation system and the bypass valve operation output value generated from the normal bypass valve operation system match, the normal bypass valve operation system should be restored. Even if the turbine bypass valve opening degree after switching is still not appropriate due to the non-linear characteristics of the turbine bypass valve 9 or delay in control response, the If this were the case, the problem would be that we would have no choice but to accept this as is.

This invention was made in view of the above problems,
The purpose of this is that in this type of turbine bypass valve control system, even after automatic switching from the normal bypass valve operation system to the emergency bypass valve operation system, the turbine bypass The purpose is to enable manual adjustment of the opening of the valve.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above object, the present invention has an automatic mode and a manual mode, and in the automatic mode, the bypass flow rate is detected and the set flow rate is While generating the bypass valve operation output using a closed loop,
In the manual mode, the normal bypass valve operation system generates a manually determined operation output, and when the operation starts, the bypass valve operation output corresponding to the turbine input flow rate immediately before tripping is generated in an open loop, and gradually a V4 leisure bypass valve operating system that automatically returns to the normal bypass valve operating system when the operating output value matches the operating output value from the normal bypass valve operating system while decreasing the operating output value; In a turbine bypass valve control device that automatically switches from a normal bypass valve operation system to an emergency bypass valve operation system in response to a turbine trip, based on a return command given from the outside, The present invention is characterized by providing means for forcibly returning from the emergency bypass valve operation system to the normal bypass valve operation system, and configured so that the bypass valve opening degree can also be manually adjusted after a turbine trip. It is.

(Function) According to such a configuration, even after automatic switching from the normal bypass valve operating system to the emergency bypass valve operating system, the emergency bypass valve operating system can be switched from the normal bypass valve operating system to the emergency bypass valve operating system at any time if necessary. The bypass valve operation system can be returned to the bypass valve operation system when forced, so if the turbine bypass valve opening is inappropriate after automatic switching to the emergency bypass valve operation system, the By forcing a return from the emergency bypass valve operation system to the normal bypass valve operation system, and then using the manual mode in the normal bypass valve operation system, the opening degree of the turbine bypass valve can be adjusted as appropriate. It becomes possible.

(Example) Fig. 1 shows control 2I of a turbine bypass valve according to the present invention.
FIG. 1 is a block diagram showing one embodiment of an I device.

As shown in the figure, this control device is mainly composed of a switching device 11 and a loop controller 12.

Inside the switch 11, there is an automatic-manual switch 11a.

An operation system selector 11b, a flow rate opening degree calculator 11C, a control knob 11d, and an OR circuit 11e are provided.

The loop controller 12 and the automatic/manual fh switch 11a constitute the above-mentioned normal bypass valve operation system, and the flow rate opening degree calculator 110 constitutes the above-mentioned emergency bypass valve operation system.

The operating system selector 11b switches the operating system for operating the bypass valve between the normal bypass valve operating system and the emergency bypass valve operating system based on the output of the flip-flop 11d.

The flip-flop lid is set in response to the trip signal 14 and reset in response to the output of the OR circuit 118.

The OR circuit 11e is configured to output the logical sum of the manipulated variable match signal 15 and the return command signal 16.

The flow rate opening calculation unit 11c receives the turbine inlet steam flow rate signal 1.
3, the turbine bypass valve opening required to allow the flow rate to flow is calculated.

Next, the operation of the control device having the above configuration will be systematically explained.

When the turbine is operating normally, the flip-flop lld has been reset, and therefore the operating system selector 11b selects the bypass valve operating system during normal operation.

In this state, the automatic mode and the manual mode 171E can be arbitrarily selected by operating the automatic-manual switch 11a.

In the automatic mode, as explained in FIG. 2, the bypass flow rate is detected via the turbine bypass flow meter 8 and the bypass valve operation output is controlled in a closed loop using the loop controller 12 so that the bypass flow rate becomes the set flow ff1sV. generated and fed to the turbine bypass valve 9.

Note that at this time, the opening degree of the turbine bypass valve 9 is a constant minute opening degree, and this is to slightly divert the steam remaining in the main flow path 4 to the condensing equipment 3.

In the manual mode, the operation output from the loop controller 12 is disconnected, and a corresponding operation output is generated according to the operation of an operation dial, operation lever, etc. (not shown), and this is applied to the turbine bypass valve 9.

This makes it possible to arbitrarily adjust the opening degree of the turbine bypass valve 9 by manual operation.

On the other hand, while operating with the normal bypass valve operation system, the turbine 2
When tripped, the flip 70 knob 11d is reset in response to the trip signal 14, thereby switching the operating system selector 11b from the normal bypass valve operating system to the emergency bypass valve operating system.

Then, the flow rate opening calculation unit 11c generates a bypass valve operation output corresponding to the turbine inlet flow rate immediately before the turbine trip based on the turbine inlet steam flow rate signal 1q obtained from the turbine inlet steam flow meter 6 in an open loop, This is given to the turbine bypass valve 9.

Thereby, the opening degree of the turbine bypass valve 9 is instantaneously widened, and pressure fluctuations caused by the turbine inlet cutoff valve being shut off can be absorbed.

Thereafter, the manipulated output value output from the flow circuit calculator 110 is gradually reduced, and when it matches the manipulated output value from the normal bypass valve operating system, the operating force matching signal 1
5 is generated, thereby resetting the flip 70 knob 11d and switching the operating system selector 11b from the emergency bypass valve operating system to the normal bypass valve operating system.

Next, the forced switching operation from the emergency bypass valve operation system to the normal bypass valve operation system, which is a main part of the present invention, will be explained.

The operation panel of this turbine bypass valve control device includes:
For example, a push button switch for forced return is newly provided.

Then, when this push button switch is suppressed,
A return command signal 16 is generated.

This return command signal 16 can reset the flip 7Cl knob 11d via the OR circuit 11e.

Therefore, when the push button switch for forced return is operated, the flip 70 knob 11d is immediately reset without the operation force matching signal 15 being generated, thereby causing the operation system selector 11b to be bypassed in an emergency. It is possible to change from a valve operation system to a normal bypass valve operation system.

After that, during normal operation by the bypass valve operation system,
When the automatic-manual switch 11a is switched to manual mode, the built-in dial is activated as described above.

The opening degree of the turbine bypass valve 9 can be adjusted arbitrarily by generating an arbitrary operation output value by operating a lever or the like and applying it to the turbine bypass valve 9 .

Therefore, although the normal bypass valve operation system was switched to the emergency bypass valve operation system in response to the turbine trip, if the opening degree of the turbine bypass valve 9 is inappropriate, the return operation is immediately performed. By operating the push button, a return command signal 16 is generated to switch from the emergency bypass valve operating system to the normal bypass valve operating system, and then by setting the automatic-manual switch 11a to manual mode, the turbine bypass The opening degree of the valve 9 can be adjusted appropriately while looking at the steam reservoir pressure gauge 10, for example.

[Effects of the Invention] As is clear from the above explanation, according to the present invention, although automatic switching from the normal bypass valve operation system to the emergency bypass valve operation system is performed in response to a turbine trip, If the opening degree of the turbine bypass valve is still not appropriate, switch to the normal bypass valve operating system by manual operation without automatically returning to the normal bypass valve operating system, and then switch to manual mode. By selecting , the opening degree of the turbine bypass valve can be arbitrarily modified, and the usability of this type of control device can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a control device according to the present invention, and FIG. 2 is a piping system diagram of steam turbine equipment to which the present invention is applied. 2...Turbine 5...Bypass passage 6...Turbine inlet steam flow td meter 8...Turbine bypass flow meter 9...Turbine bypass valve 11...Switcher 1a...Automatic - Hand/V switch 1b...Operating system selector 1C...Flow rate y1 operator 1d...Flip-flop 1e...OR circuit 2...Loop controller 3...Turbine inlet steam flow rate signal 4...Trip signal 5...Operation output coincidence signal 6...Return command signal

Claims (1)

[Claims] It has an automatic mode and a manual mode, and in the automatic mode, the bypass flow rate is detected and a bypass valve operation output is generated using a closed loop so that this becomes the set flow rate, while in the manual mode, the bypass valve operation output is generated so that the bypass flow rate becomes the set flow rate. The system includes a normal bypass valve operating system that generates a manually determined operating output, and an open-loop bypass valve operating system that generates a bypass valve operating output corresponding to the turbine inlet flow rate immediately before tripping at the start of operation, and gradually increases the operating output value. and an emergency bypass valve operating system that automatically returns to the normal bypass valve operating system when the operating output value matches the operating output value from the normal bypass valve operating system, and responds to a turbine trip. In a turbine bypass valve control device that automatically switches from a normal bypass valve operating system to an emergency bypass valve operating system, the emergency bypass valve operating system automatically switches based on a return command given from the outside. 1. A control device for a turbine bypass valve, characterized in that a means for forcibly returning the bypass valve operating system to a normal bypass valve operation system is provided, and the bypass valve opening degree can also be manually adjusted after a turbine trip.