JPS59150908A - Turbine control device - Google Patents

Abstract

PURPOSE:To prevent a turbine trip by providing a pilot valve control means in a reducing valve control system for a steam turbine so that when a differential value between input and output signals for an actuator to actuate a servo valve exceeds a specified value, the reducing valve may gradually be closed by said control means. CONSTITUTION:In a control system for a steam reducing valve 12, a pilot valve control means 6 connected to a lever 16 is provided between an actuator whose actuation is controlled by a servo valve 2 and a pilot valve 10. A control signal from a control unit 1 to the servo valve 2 and an output signal from a differential transducer 4 are compared at the control unit 1, and their deviation is compared with a signal from a deviation value setting means 19 by a comparator 20. When the deviation exceeds the set value, a judgement that there exists a failure in the servo valve, etc. is made, and a backup motor 22 is operated to gradually close the reducing valve by the pilot valve control means 6 to reduce the load so that the turbine may be continuously operated without tripping it even when a failure occurs in the servo valve.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a turbine control device suitable for reducing the influence on a turbine plant during failure and maintenance of a servo valve in a control system of a steam turbine. [Prior Art] As shown in FIG. 1, a control valve 12 that controls the speed and load of a steam turbine is operated by a servo motor 11 operated by a pilot valve 10. Pilot valve 1
0 is operated by a servo valve 2, an actuator 3, etc. operated by a control unit 1. A control oil 15 is supplied to the pilot valve 10 and the servo valve 2, and in some steam turbines, the control oil 15 and lubricating oil are the same, which poses a problem in the cleanliness of the control oil 15.

The servo valve 2 is a precision device, and if the cleanliness of the control oil is poor, failure will occur. In the conventional turbine control device shown in Fig. wJ1, if the servo valve 2 fails, the turbine must be tripped, and load fluctuations are large during high-load operation, which adversely affects the turbine plant. or,
Failure of the servo valve 2 could not be detected early, which caused problems in terms of maintenance and management.

That is, as shown in FIG. 1, a servo valve 2 is connected to a control unit 1 that controls the speed and load of a steam turbine, and control oil is sent to the servo valve 2 via a filter 14. Servo valve 2 receives input electricity 1δ from the control unit.
This hydraulic signal is sent to the actuator 3 to operate it. A lever 16 is connected to the actuator 3 via a spring 5. The lever 16 is connected to the pilot valve 10 and the servo motor 11 by forming a link mechanism. Further, as described above, the servo motor 11 is connected to the control valve 12 via the link mechanism.

With the above configuration, the input electric signal of the control unit 10 is input to the servo valve 2, the output number 1a is output from the actuator 3 correspondingly, and the control valve 12 is controlled by the lever 16 via the pilot valve 10 and the servo motor 11. operate and control the speed and load of the steam turbine.

As described above, the control oil 15 is introduced into the servo valve 2 through the filter 14, but if the cleaning is insufficient, problems such as closing the minute gaps in the servo valve 2 may occur, resulting in the servo valve 2 to malfunction. If the servo valve 2 breaks down, a problem occurs in which the input electrical signal and the output No. 18 do not match, so the turbine must be tripped. Therefore, if servo valve 2 fails during high load operation,
It is not possible to gradually lower the negative TIt, and a large load change occurs, which has a negative impact on the turbine plant. Further, the turbine must be stopped for π9 inspection of the servo valve 2 or replacement in case of failure, which causes a decrease in the operating rate of the turbine plant.

1. [Purpose of tilting] The present invention was devised to solve the above-mentioned problems and drawbacks, and its purpose is to be able to detect abnormalities in the servo valve at an early stage, and also to enable the turbine to be operated even in the event of an abnormality. Turbine load can be gradually reduced without tripping,
and a turbine control device t'& that allows maintenance inspection and replacement of the servo valve without tripping the turbine.
It is about providing.

[Summary of the Invention] In order to achieve the above object, the present invention includes a pilot valve operating means connected at a predetermined interval to a lever between an actuator and a pilot valve, and an electric signal input from a servo valve and an electric signal from the actuator. Detects the deviation value from the output signal of the controller, compares the deviation value with a predetermined deviation set value, and operates the pilot valve operating means only when the deviation value exceeds the deviation set value. a deviation value detection comparison means,
An on-off valve is provided between the servo valve and a control oil supply line that supplies control oil to the servo valve, and detects an abnormality in the servo valve based on the deviation value, and in the event of an abnormality, a pilot valve operating means is used to control the servo valve. operate the pilot valve;
The present invention is also characterized by a turbine control device that closes the on-off valve and performs maintenance inspection or replacement of the servo valve.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described based on the drawings.

First, an overview of this embodiment will be explained.

As shown in FIG. 2, the actuator 3 and the pilot valve 10
A pilot valve operating means 6 connected to the lever 16 is connected between the lever 16 and the lever 16 . The pilot valve operating means 6 is connected to the lever 6 by a spring 9 having a spring constant stronger than that of the spring 5 of the actuator 3, and the spring 9 is connected to a jacking member, which is one of the above-mentioned moving means, which engages at a predetermined interval. Grod 8 is engaged.

The deviation value detection comparison means 17 detects the output 1 of the actuator.
Differential transformer 4 for detecting the signal, deviation set value setting means 1
9, deviation value comparison means 20, vi@ means 18, etc. The output signal from the differential transformer 4 and the input ε heat signal of the servo valve 2 are compared by the control unit 1 and a deviation value thereof is determined. This deviation value and the deviation setting value from the deviation setting 1 direct setting 19 are compared by the deviation value comparing means 20. When the deviation value exceeds the deviation set value, an operation command is input to the pilot valve operating means 6, the jacking rod 8 engages with the spring 9, and the pilot valve 10 is operated via the lever 16. Gradually reduce the turbine load.

On the other hand, an on-off valve 13 is provided between the control oil supply line 23 in which the filter 14 for the control oil 15 is provided and the servo valve 2 . When the servo valve 2 is abnormal, the on-off valve 13
Closed, inspected, replaced, etc. During this time, the pilot valve 10 can be operated by the pilot valve operating means 6.
Operation can be continued without tripping the turbine.

Next, this embodiment will be explained in more detail.

In FIG. 2, the same reference numerals as in FIG. 1 indicate the same snout or the same geometry.

First, the pilot valve operating means 6t will be explained.

As described above, one end of the spring 9 having a stronger spring constant than the spring 5 is connected via the rod 24 between the position where the spring 5 of the actuator 3 of the lever 16 is connected and the pilot valve 10 .

Specifically, one end of the rod 24 is pivotally connected to the lever 16, and the other end engages with one end of the spring 9, either directly or at a distance. One end of a jacking rod 8, which is one of the moving means, is engaged with the other end of the spring '9 at a predetermined interval. This predetermined interval is set to an appropriate dimension, but during steady operation, it limits the movement of the lever 16 that is displaced by the actuator 3.
9, which limits the output No. 16 of the lever 16, is set to an interval that does not interfere with the movement of the lever 16, and is set to operate following the actuator 3. A screw is threaded on the other end of the jacking rod 8, and the screw is engaged with a nut provided on the fixed side of the device. Further, a handle 7 for manually rotating the worm gear 21 and the jacking rod 8 is fixedly provided on the other end side. In addition, the worm gear 21 is connected to the loose body up motor 2.
Pinion gear 25 connected to 2 meshes with each other. According to the above configuration, when the backup motor 20 is rotated, the jacking rod 8 moves and is locked to the spring 9, thereby levering the lever 16t.
- Works.

Next, the deviation area detection and comparison means 17 will be fully explained.

A differential transformer 4 is connected to the actuator 3 for detecting its output signal and detecting the displacement of the actuator 3. This detected value is input to the control unit 1, and the deviation value from the input electricity No. 1g of the servo valve 2 is detected. During steady operation when no abnormality occurs in the servo valve 2, the deviation value is automatically controlled to be zero.

A deviation value comparison means 20 is connected to the control unit 1, and the deviation value is inputted thereto. Further, the deviation value comparison means 20 includes:
The deviation set value determined by the deviation set value setting means 19 is input and compared with the above deviation value. The deviation value that occurs when an abnormality occurs in the servo valve 2 is set as the deviation setting value.

The deviation value comparison means 20 is configured to give a rotation instruction to the backup motor 22 and cause the alarm device 18 to issue an alarm when the deviation value exceeds the deviation setting value.

Next, an on-off valve 13 is provided between the control oil supply line 23 through which the control oil 15 flows and the servo valve 2 . Opening/closing 13f: By closing, the introduction of control oil to the servo valve 2 is restricted.

Next, the operation of this embodiment will be explained with reference to FIG.

The detected displacement of the differential transformer 4 is fed back to the control unit 1, and the deviation value is detected as described above.

Next, the deviation value comparison means 20 compares the deviation value with the deviation setting value as described above, and when the deviation value exceeds the deviation setting value, a -signal vi- is issued and the 1-backup motor 22 is rotated. .

This causes the pinion gear 22 and worm gear 21 to rotate and move the jacking rod 8. When the jacking rod 8 engages with the spring 19, the spring 9 overcomes the spring 5 due to its strong spring constant and moves the lever 16. Thereby, the lever 16 is operated by both the actuator 3 and the pilot valve operating means 60.

The deviation value exceeds the deviation set value when an abnormality occurs in the servo valve 2, and the abnormality in the servo valve 2 is discovered at an early stage. In this state, the on-off valve 13 is closed and the operation of the lever 16 by the servo valve 2 is stopped, but the lever 16 is operated by the above-mentioned pilot valve operating means 6, and via the pilot valve 10 servo motor 11, Control of the regulating valve 12 is performed continuously. In addition, in order to gradually reduce the load,
Sudden fluctuations in turbine load do not occur. Therefore, it does not adversely affect the turbine plant.

Also, by closing the on-off valve 13t, the servo valve 2 is inspected while the turbine continues to operate.
4 and the spring 9, and between the spring 9 and the jacking rod 8, it becomes possible to finely adjust the movement of the leno (16) during normal or abnormal operation.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, it is possible to detect an abnormality in a servo valve at an early stage, and at the time of an abnormality, the turbine load is gradually lowered without tripping the turbine. It is possible to prevent # from being applied, and the servo valve can be inspected or replaced while driving continues.

[Brief explanation of drawings]

Figure 1 is a configuration diagram showing a conventional turbine control device;
The figure is a configuration diagram showing one embodiment of the present invention, and FIG. 3 is a control block diagram for explaining the entire operation of the above-mentioned embodiment. DESCRIPTION OF SYMBOLS 1... Control unit, 2... Servo valve, 3... Actuator, 4... Differential transformer, 5... Spring, 6... Pilot valve operating means, 7... Knoll handle , 8... Jacking rod, 9... Spring, 10
...Pilot valve, 11...Servo motor, 12.
...Adjustment valve, 13...Opening/closing valve, 14...Filter,
15... Control oil, 16... Lever, 17... Deviation value detection comparison means, 18... Time signal, 19... Deviation set value setting means, 20... Deviation value comparison means, 21... Worm gear, 22... Backup motor, 23...
・Control oil supply line, 24...rod, 25...1
111 Exit 2m

Claims (1)

[Claims] 1. Connected to the control oil supply line and controlling the speed of the steam turbine;
a servo valve that converts an input electrical signal from a control unit that controls a load into a hydraulic signal; an actuator that is connected via a spring to a lever that operates a pilot valve t7th and that operates the lever in response to the servo valve; A turbine control device comprising a servo motor operated by the pilot valve to operate a regulating valve that adjusts the speed and load of the steam turbine, the actuator being connected at a predetermined interval to the lever between the pilot valve. The pilot valve operating means detects the deviation value between the input 'hypogastric signal of the servo valve and the output signal output from the actuator, and compares the deviation value with a predetermined deviation setting value, It is characterized by comprising a deviation value detection and comparison means that operates the pilot valve operating means only when the deviation value exceeds the deviation set value, and an on-off valve provided between the control oil supply line and the servo valve. Turbine control device. 2. The pilot valve operating means is connected to the lever, and has a spring having a stronger spring constant than the spring connected to the actuator, and a jacking rod that engages the spring at the predetermined interval; It is composed of a moving means for moving the jacking rod so as to engage the jacking rod, and a backup motor connected to the moving means and operated by a command from the deviation value detection and comparison means. A turbine control device according to claim 1.