JPH06307204A - Steam turbine controller - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to obtain a steam turbine control device capable of improving the reliability of detection of a limit switch of a steam control valve and a differential transformer. According to a configuration of the present invention, in a steam turbine control device for controlling a turbine rotation speed by controlling a steam flow rate with a steam control valve, a light source body disposed near a valve rod of the steam control valve, An optical sensor for detecting the position of the valve rod and arranged with a gap between the valve rod and a detector for detecting an abnormality of the optical sensor and the light source body are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam turbine controller for controlling a steam turbine.

[0002]

2. Description of the Related Art Generally, a limit switch or a micro switch system is adopted as a fully closed point or a fully opened point (on / off) detector as a method for detecting a control valve position of a steam turbine controller in a power plant, and a fully closed valve is also used. A differential transformer system is adopted as a detector that detects the stroke from the full opening to the full opening.

FIG. 5 is a block diagram showing a conventional steam turbine control device having a limit switch and a differential transformer system. The steam control valve 2 is controlled by the process quantity valve position control signal a output from the control unit 1 of the steam turbine control device.
Is controlled to open and close. As a result, the steam b flowing into the steam turbine 3, which is the main engine, is controlled, and the rotation speed of the steam turbine 3 is controlled. The output of the generator 4, which is the main engine, is paralleled to the system 6 via the parallel circuit breaker 5. Reference numeral 7 is a valve rod connected to the steam control valve 2, and 8 is a limit switch mounted adjacent to the valve rod 7. The limit switch 8 detects the fully closed point or the fully opened position of the steam control valve 2 and outputs it to the control unit 1. On the other hand, the differential transformer 9 is attached to the valve rod 7 to detect the process amount during the entire stroke of the steam control valve 2 from fully closed to fully opened, and the differential transformer 9 is used as a valve position feedback signal d of the steam turbine. Output to the control unit 1.

According to the process quantity valve position control signal a set by the control unit 1 of the steam turbine, the steam control valve 2 is controlled to a certain specified value. The steam b flows into the steam turbine 3 based on the flow rate characteristic of the steam control valve 2, and the rotation speeds of the steam turbine 3 and the generator 4 directly connected to each other are the target rotation speed set by the control unit 1 of the steam turbine, in other words, the target rotation speed. It is controlled by the target process amount valve position control signal a. The target rotation speed set by the control unit 1 of the steam turbine is set at the time when the feedback amount of the valve position feedback signal d becomes the same process amount, in other words, the steam control valve 2 sets the steam amount enough to generate the target rotation speed. The control is completed while it is being controlled, and it is balanced in a closed loop.

[0005]

However, in this state, if the differential transformer 9 or the limit switch 8 malfunctions such as failure, disconnection, misalignment, short circuit, etc., the input to the control unit 1 of the steam turbine is important. The feedback signal disappears and control is lost. As a result, the steam control valve 2 may be controlled to open or close abnormally, the rotation speed of the steam turbine may be controlled to overspeed or lose speed, and the steam turbine may be stopped.

These detectors have many problems such as difficulty in mechanical adjustment, misalignment and damage due to wear.
Even if an attempt is made to multiplex in order to maintain these reliability, there is a problem in securing a mounting space for the detector.

[0007] In recent steam turbine control devices for power plants, it is required to expand the control range, and there is a trend toward higher functionality through the adoption of digitalization. or,
As a result, demands for higher reliability and improved operating efficiency are increasing more than ever before, and it is also important to enhance the failure diagnosis function for the purpose of early detection of defective parts before they affect the operation of the power plant. It is becoming a required item.

[0008] A single failure of the limit switch for detecting the valve position or the differential transformer, an adjustment deviation due to mechanical structural requirements, a decrease in accuracy due to hysteresis, a short circuit due to mechanical wear, a disconnection, or the like occurs. If it does, the steam turbine can be stopped, but since it is stopped in an emergency, it causes a large power fluctuation in the power transmission system, which causes a socially large power supply failure.

An object of the present invention is to improve the reliability of the limit switch for detecting the valve position, which is the most important sensor during the operation of a steam turbine, and the detection method for each of the differential transformers, and to prevent the failure of a single system. It is to obtain a steam turbine control device capable of stably continuing the current status maintenance operation without stopping the steam turbine even if the above occurs.

[0010]

In order to solve the above-mentioned problems, in the present invention, in a steam turbine control device for controlling a turbine speed by controlling a steam flow rate with a steam control valve, the steam control valve A light source arranged near the valve stem, an optical sensor for detecting the position of the valve stem and arranged with a gap with the valve stem, and a detector for detecting an abnormality of the optical sensor and the light source. There is provided a steam turbine control device characterized by being provided.

[0011]

In the device thus constructed, the valve position is detected in a non-contact manner, so that a mounting space can be easily secured and adjusted, accuracy can be improved, and mechanical wear can be reduced. .

[0012]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2 are configuration diagrams showing an embodiment of a steam turbine control device according to the present invention. This embodiment is an embodiment in which an optical sensor is used to detect the valve stroke of the steam control valve and the valve opening / closing detection.

In FIG. 1, reference numeral 10 is a light source installed adjacent to the valve rod 7 and is a light source for operating the valve stroke light sensor 14 and the valve opening / closing sensor 15. Reference numeral 11 denotes a signal abnormality detector for detecting a single system abnormality of the light source body 10. When the light source body 10 becomes abnormal, the output signal A of the signal detector is set to "1" and the failure indicator 16 of FIG. Output to. The valve stroke optical sensor 14 digitally detects the stroke amount of the steam control valve 2 installed adjacent to the valve rod 7 from full closing to full opening, and outputs it as a valve position feedback signal d via an optical cable to the steam turbine. Output to the controller 1. The signal abnormality detector 13 detects a single system abnormality (including an output abnormality signal) of the valve stroke optical sensor 14. When detecting the abnormality, the signal abnormality detector 13 sets the abnormality signal C of the signal abnormality detector 13 to "1" and outputs it to the failure detector 16. The valve opening / closing sensor 15 detects a fully closed point and a fully opened point of the steam control valve 2 installed adjacent to the valve rod 7 and outputs the detected point to the control unit 1 of the steam turbine via an optical cable. Signal abnormality detector 12
Detects an abnormality (including an output abnormality signal) of a single system of the valve opening / closing light sensor 15. When the signal abnormality detector 12 detects an abnormality, the abnormality signal B of the signal abnormality detector 12 is set to "1",
Output to the failure indicator 16. The fault indicator 16 is ORed when "1" is input to any one of the three input signals.
The circuit outputs an alarm.

According to this embodiment, the valve stroke sensor which is an important sensor in the control device 1 of the steam turbine is used.
By making the valve 14 and the valve opening / closing light sensor 15 non-contact with the valve rod 7 main body, it is possible to eliminate troubles due to mechanical wear and misalignment, and it is possible to improve accuracy by a digital method. Further, since the signal is input to the control unit 1 of the steam turbine via the optical cable, there is no need to worry about troubles or the like due to noise that has been conventionally mixed in the cable. In this way, the reliability of controllability can be improved.

3 and 4 are block diagrams showing another embodiment of the present invention. This embodiment is an embodiment in which the optical sensor is tripled. In FIG. 3, the steam control valve 2
Valve stroke light sensor, valve stroke light sensor
14a, a valve stroke light sensor 14b, and a valve stroke light sensor 14c are respectively provided and tripled. Similarly, the signal abnormality detectors are also the signal abnormality detector 13a and the signal abnormality detector 13
b, the signal abnormality detector 13c is tripled. The outputs of the valve stroke optical sensors 14a, 14b, 14c are input to an intermediate value selector (hereinafter referred to as MVG) 18, and the MVG 18 outputs an intermediate value signal of the three input signals to the control unit 1 of the steam turbine. To do.

On the other hand, the valve opening / closing optical sensor of the steam control valve 2 is also tripled with the valve opening / closing sensor 15a, the valve opening / closing optical sensor 15b, and the valve opening / closing optical sensor 15c. The signal abnormality detector is also a signal abnormality detector 12a, a signal abnormality detector 12b, and a signal abnormality detector.
It is tripled with 12c. Valve open / close optical sensors 15a, 15b,
The output of 15c is 2 OUT OF 3 logic 17 (hereinafter 2/3
It is input to 2/3 logic 17,
Two or more normal signals of the three signals are output to the control unit 1 of the steam turbine.

Signal abnormality detectors 12a, 12b, 12c, 13a,
When an abnormality is detected, 13b and 13c output signal abnormality detector output signals B-1, B-2, B-3, C-1, C-2, C-3.
“1” is set as the minor fault indicator 20 and the major fault indicator 19 in FIG.
Output to. The minor fault indicator 20 outputs a minor fault alarm by the OR circuit when "1" is inputted to any one of the six inputted. The serious failure indicator 19 outputs an alarm of a serious failure by the OR circuit when the abnormal signal A of "7" is inputted among the seven inputted signals.

On the other hand, the abnormal signals B-1, B-2, B-3
In the group, two or more of these signals become "1" and a serious failure signal is output. Similarly, as for the abnormal signals C-1, C-2, and C-3, two or more signals among them become "1" as one group, and a serious failure signal is output.

According to this other embodiment, the valve stroke light sensor 14 and the valve opening / closing sensor 15 are tripled,
Even if a single system failure occurs, MVG 18, 2/3 logic 17
With this circuit, the steam turbine can be stably operated in the current state without being affected. In these examples,
Although the explanation was made for the steam control valve, other main steam stop valves,
It can also be applied to control circuits such as intercept valves.

[0020]

According to the present invention, since the non-contact type optical sensor is adopted in the steam turbine controller, the accuracy of controllability can be improved. Furthermore, even if a single system failure of each sensor occurs, the steam turbine will not be brought to an emergency stop, there will be no large power fluctuations in the power transmission system, and stable operation can be maintained as is. Reliability can be improved. Further, since the non-contact type system is adopted from the conventional mechanical system, it is easy to secure a mounting space and adjust.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram showing an embodiment of a steam turbine control device according to the present invention.

FIG. 3 is a configuration diagram showing another embodiment of the steam turbine control device according to the present invention.

FIG. 4 is a configuration diagram showing another embodiment of the steam turbine control device according to the present invention.

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

[Explanation of symbols]

1 ... Control unit, 2 ... Steam control valve,
3 ... Steam turbine, 4 ... Generator, 5 ...
Parallel circuit breaker, 6 ... system, 7 ... valve stem,
8 ... Limit switch, 9 ...
Differential transformer, 10 ... Light source, 11, 12,
12a, 12b, 12c, 13a, 13b, 13c ... Signal abnormality detector, 14, 14a, 14b, 14c ... Valve stroke optical sensor,
15,15a, 15b, 15c ... Valve opening / closing light sensor, 16 ... Fault display, 17 ... 2 OUT OF 3 (2/3)
Logic, 18 ... Intermediate position selector (MVG), 19 ... Major fault indicator, 20 ... Minor fault indicator, A, B, C, B-1,
B-2, B-3, C-1, C-2, C-3 ... Abnormal signal,
a ... Process amount valve position control signal, b ... Steam, d ... Valve position feedback signal.

Claims (4)

[Claims] 1. A steam turbine control device for controlling a turbine rotation speed by controlling a steam flow rate with a steam control valve, a light source body disposed near a valve rod of the steam control valve, and a position of the valve rod. A steam turbine control device comprising: an optical sensor that performs detection and is arranged with a gap from the valve rod; and a detector that detects an abnormality of the optical sensor and the light source body. 2. The light sensor includes a valve opening / closing light sensor for detecting a fully closed position and a fully opened position of the steam control valve, and a valve light stroke for detecting a full stroke of the steam control valve from fully closed to fully opened. The steam turbine control device according to claim 1, further comprising a sensor. 3. A valve opening / closing light sensor and a valve light stroke sensor, which are respectively installed in triplicate, and three signals of the valve opening / closing light sensor, which are triplicated, are input, and two or more coincident signals are output. 2/3 logic, an intermediate value selector for inputting three signals of the triple valve light stroke sensor and outputting an intermediate value signal, and one of the valve opening / closing light sensor and the valve light stroke sensor The steam turbine control device according to claim 2, further comprising a failure indicator that outputs an alarm when the above abnormality occurs. 4. A valve closing / opening light sensor and a valve light stroke sensor, which are installed in triplicate, and three signals of the valve opening / closing light sensor, which are triplicated, are input and two or more coincident signals are output. 2/3 logic, an intermediate value selector that inputs three signals of the valve light stroke sensor that are tripled and outputs an intermediate value signal, and two of the triple valve open / closed light sensors The above-mentioned abnormality is detected and an alarm is output, two or more of the triplicate valve light stroke sensors are detected and an alarm is output, and an abnormality of the light source is detected and an alarm is output. 3. The steam turbine control device according to claim 2, further comprising a failure indicator.