JPH02267302A - Steam valve abnormality diagnosis system - Google Patents

Abstract

PURPOSE:To make it possible to discover the occurrence of abnormality at an early stage by controlling a steam valve on the basis of deflection between a valve opening setting signal set in accordance with the load and the rotating speed of a steam turbine and an actual valve opening position signal and judging it as abnormality of the steam valve in the case when the deflection continues for more than a specific time. CONSTITUTION:The output of an adder 4 to obtain deflection between a valve opening setting signal calculated from the rotating speed, a load instruction and others and an actual opening position signal is amplified 8 and input in an electric and hydraulic converter 9, and an operation cylinder 10 is actuated in accordance with a hydraulic signal gained therein. Thereby, a pilot valve 12 is controlled through a lever 11 to drive an oil cylinder piston 13 and the valve opening of a steam valve 1 is controlled. ln this case, converters 5, 17 to detect the change of the mechanical positions of the operation cylinder 10 and the oil cylinder piston 13 are provided and their output is input in an abnormality diagnosis system 16 as a valve opening setting signal 6 and an actual valve opening position signal 7. When the deflection between the both signals 6, 7 continues for more than a specific time, it is judged as the abnormality of the steam valve 1.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a steam valve that quickly detects abnormalities in a steam valve that controls the amount of steam flowing into a steam turbine and safely protects equipment. The present invention relates to an abnormality diagnosis device.

(Prior Art) A steam turbine is installed with a steam valve that controls 11 the amount of steam flowing into the steam turbine according to the load, turbine rotational speed, and operating state of the steam turbine.

This steam valve amplifies the width difference signal between the steam valve opening setting signal, which is set according to each load, turbine rotation speed, etc., and the actual valve opening position signal, which indicates the actual steam valve opening position. The opening degree is controlled by controlling the amount of oil supplied to the oil cylinder by inputting it to the electric/hydraulic converter. In other words, in such a control system, an electro-hydraulic control device is used in which calculation and transmission are performed electrically, and operating force is handled hydraulically.

FIG. 8 shows a part of the control system diagram of the electro-hydraulic control device for the steam valve 1, and particularly shows the valve position control circuit extracted.

A governor signal 2 calculated from operating conditions such as turbine rotation speed and load command is input to a valve opening function 3. The valve opening degree function 3 calculates a valve opening degree setting signal 6 for the steam valve corresponding to the governor signal 2, and outputs it to the adder 4.

On the other hand, the actual mechanical opening change of the steam valve 1 is converted into an electrical signal as an actual valve opening position signal 7 by the converter 5,
This actual valve opening position signal 7 is also input to the adder 3.

In the adder 3, the valve opening degree setting signal @6 is set as +, and the actual valve opening position signal 7 is set as -, and both signals are added.

A weak deviation signal between the two signals is amplified by an amplifier 8 and then input to an electric/hydraulic converter 9. The electric/hydraulic converter 9 converts the amplified deviation signal value into a hydraulic signal, and supplies hydraulic oil corresponding to the hydraulic signal to the operating cylinder 10.

The operating cylinder 10 uses mechanical output obtained from hydraulic oil to drive a pilot valve, a lever link structure, an oil cylinder piston, etc., which will be described later, and adjusts the valve opening of the steam valve 1 to a predetermined value. As described above, the mechanical position change of the operating cylinder 10 is controlled by the converter 5 as an electrical actual valve opening position signal 7.
is converted to

A closed loop control circuit is constructed in which this actual valve opening position signal 7 is fed back to an adder 4.

Based on the electrical control system as described above, the control system including the mechanical configuration will be further explained with reference to FIG. 9.

That is, in FIG. 9, an electric signal from an amplifier 8 and a control 1 hydraulic oil from an oil pump (not shown) are supplied to the air/hydraulic converter 9. The electro-hydraulic converter 9 operates the control hydraulic oil according to the electric signal to the upper bow 1- of the cylinder 10.
and configured to supply the lower port. Further, a converter 5 is directly connected to the operating cylinder 10, and an electric signal detected by the converter 5 in response to a change in the position of the operating cylinder 10 is transmitted to the converter 4 as an actual valve opening position signal 7. be done.

On the other hand, the mechanical output on the upper end side of the operating cylinder 10 is the lever 1
1 to the pilot valve 12 to drive the pilot valve 12. The pilot valve 12 operates to switch oil passages in order to supply control oil from an oil pump (not shown) to the lower part of the oil cylinder piston 13. Pilot valve 1
The flow rate of the control oil supplied to the pump 2 is adjusted by an orifice 14 arranged in the oil passage.

Further, a steam valve 1 is connected to the tip of the oil cylinder piston 13,
A lever 15 is connected in the middle of the connecting portion, and a mechanical feedback mechanism is configured to push back the pilot valve 12 via this lever 15.

In this way, the amount of mechanical change in the operation cylinder 10 is mechanically amplified in proportion to the lengths of the levers 11 and 12, and the oil cylinder piston 13 is raised and lowered, and finally the main purpose of υJtll is steam. Valve opening control (valve position control) of valve 1 is performed.

(Problem to be Solved by the Invention) As explained above, in the conventional electro-hydraulic reversible device, although the main control purpose is to control the valve opening of the steam valve 1, it is actually incorporated into the electric control circuit and controlled. What is shown is the amount of mechanical change of the operating cylinder 10. Therefore, in FIG. 9, if the valve stem of the steam valve 1 becomes stuck and causes a so-called stuck phenomenon, the lever 11.15 falls off, or the oil passage including the orifice 14 breaks, etc.
Even if a mechanical damage accident or malfunction occurs, it will not be detected as an abnormality in the control system, and as a result, steam turbine overspeed or sudden changes in load will occur, making it impossible to operate the steam turbine safely. There were some difficult issues.

The present invention has been made to solve the above problems, and it is possible to quickly detect a malfunction in a mechanical element that constitutes a control device, recognize it as a control abnormality, and safely shut down a steam turbine. The purpose of this invention is to provide a steam valve abnormality diagnosis device that can perform the following steps.

(Structure of the Invention) (Means for Solving the Problems) In order to achieve the above object, a steam valve abnormality diagnosis device according to the present invention uses a valve opening setting signal that is set according to the load and rotation speed of a steam turbine. , the position of the steam valve is controlled to eliminate the deviation from the actual valve opening position signal, and the steam valve is controlled when the deviation between the valve opening setting signal and the actual valve opening position signal continues for a predetermined time or more. The present invention is characterized in that it includes an abnormality diagnosis device that determines that there is an abnormality.

(Function) According to the steam valve abnormality diagnosis device having the above configuration, when the steam turbine plant is operating normally, the valve opening setting signal of the steam valve is sent, except during transient times such as when operating conditions are changed. and the actual valve opening position signal match.

Therefore, since no deviation between the two signals is detected, an abnormality in the steam valve is not diagnosed.

However, if a malfunction occurs in the operating cylinder, a broken lever, or a malfunction in the oil cylinder piston, the valve opening setting signal and the actual valve opening position signal will take different values, and the deviation will be caused by a temporary transient. It is not a temporary thing, but it continues over a long period of time. Therefore, when the deviation continues for more than a predetermined time,
An abnormality diagnosis device diagnoses the occurrence of an abnormality in the steam valve.

Therefore, failures occur early, restoration can be carried out quickly, and safety during operation of turbine plants and the like can be improved.

(Example) Next, an example of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a system diagram that does not show an embodiment of the steam valve abnormality diagnosing device according to the present invention. Note that the same elements as the conventional steam valve electrical 11 control system a3 shown in FIG. 8 and the conventional mechanical control system shown in FIG. do.

The steam valve abnormality diagnosis device according to the present embodiment is configured to position υJtl so as to eliminate the deviation between the valve opening setting signal, which is set according to the load and rotational speed of the steam turbine, and the actual valve opening position signal.
When the deviation between the valve opening setting signal and the actual valve opening position signal continues for a predetermined time or more, the steam valve 1
An abnormality diagnosing device 16 that determines that the abnormality is abnormal is provided.

That is, this embodiment differs in configuration from the steam valve control system shown in FIGS. 8 to 9 in that a converter 17 that electrically detects changes in the mechanical position of the oil cylinder piston 13 is provided. On the other hand, an abnormality diagnosis device is provided with a converter 5 that electrically detects changes in the mechanical position of the operating cylinder 10, inputs detection signals from the converters 17 and 5, and diagnoses whether or not there is an abnormality in the steam valve. It is located where 16 is installed.

This abnormality diagnosis device 16 has a function of diagnosing the presence or absence of an abnormality in the steam valve by combining many status values that can be a valve opening setting signal and an actual valve opening position signal, and comparing the two. , is basically constructed by circuits as shown in FIGS. 2 to 4.

That is, the abnormality diagnosis device @16a shown in FIG.
Stroke 1Ij of the operating cylinder 10 that drives the pilot valve 12 that supplies hydraulic oil to the opening/closing oil cylinder piston 13
18a is used as the valve opening setting signal 6, while the stroke 1ifi19a of the oil cylinder piston 13 is used as the actual valve opening position signal 7.

That is, the stroke value 18a of the operating cylinder 10 and the stroke value 19a of the hydraulic piston 13 are monitored, and the deviation between the two is monitored. Lever 11.15
The oil cylinder piston stroke value 19a via the constant 20a corresponding to the multiplication factor and the operation cylinder stroke 11
8a in an adder 4a, and calculate the deviation between the two.

If the deviation continues to occur even after the predetermined time set by the timer 21a, the deviation signal and the turbine rotation speed condition 22a (for example, 800 PPM or more) is input to the AND circuit 23a. When both the deviation signal and the turbine rotation speed condition 22a are satisfied, the AND circuit 23a is activated and outputs the turbine trip signal 24.

In this way, the operating cylinder 10 and the oil cylinder piston 13 are mechanically connected by the lever 11.15 as shown in FIG. (+19a means lever 1
Even if the amplification valve according to 1.15 is considered, there is always a proportional relationship during normal operation. If this proportional relationship breaks down and a deviation occurs between the two values, the abnormality diagnosis device 16a determines that there is an abnormality in the mechanical system Ill/III of the steam valve 1, and outputs the turbine trip signal 24 to safely stop the turbine. urge

The abnormality diagnosis device 16b shown in FIG. 3 has almost the same configuration as the one in FIG. .

This valve opening function stroke value 25a is obtained from the output signal of the valve opening function 3 determined by the value of the governor signal 2 shown in FIG.

That is, the valve opening function stroke 25a and the oil cylinder piston stroke value 19b are monitored, and when a deviation between the two occurs for a predetermined period of time or more, the abnormality diagnosis device 16
b determines that an abnormality has occurred between the electrical control system and the mechanical control system of the steam valve 1, and outputs a turbine trip signal 24.

The abnormality diagnosis device 16C, which is not shown in FIG.
The valve opening function stroke value 25b is used as the actual valve opening position signal 7, while the operating cylinder stroke value 18b is used as the actual valve opening position signal 7.

If the deviation between the valve opening function stroke value 25b and the operating cylinder stroke value 18b continues for more than the time set by the timer 21c, the abnormality diagnosis device 16c detects that an abnormality has occurred in the operating cylinder 10 or the electric/hydraulic converter 9. It diagnoses that this has occurred and outputs a turbine trip signal 24.

Abnormal diagnosis shown in Figures 2 to 4! Place 168~1
The 6G circuits can be used not only individually, but also by combining two or more circuits. Further, the detection of an abnormality is not limited to the case where the turbine trip signal 24 is output, but it is also possible to configure the system so that an alarm is issued simply by using the deviation signal, and it goes without saying that various circuits can be devised.

Furthermore, in the above embodiments, a control system that combines an electric/hydraulic converter and an operating cylinder is mainly described, but for example, other means may be used instead of a solenoid valve or an electric/hydraulic converter! The same application can be made to the II Ill system.

In this way, according to this embodiment, it is possible to directly compare and calculate the valve opening υJ target value and the actual value of $1, thereby diagnosing whether or not there is an abnormality in the steam valve. This can lead to a trip, and the safety of turbine plant operation can be improved.

In particular, since the location where the abnormality occurs is limited depending on the type of signal used as the valve opening degree setting signal and the actual valve opening position signal, the location of the abnormality can be easily identified and the abnormality location can be recovered at an early stage.

Next, a modification of the present invention will be explained with reference to the accompanying drawings FIGS. 5 to 7.

FIG. 5 shows the control circuit of the embodiment shown in FIG. 1, which detects the fully open position and the fully open position of the oil cylinder piston 13, respectively, instead of the converter 17 that electrically detects changes in the mechanical position of the oil cylinder piston 13. fully open limit switch 26,
An example is shown in which a fully open limit switch 27 is installed and the detection signals thereof are input to the abnormality diagnosis device 16d.

The control circuit of the abnormality diagnosis device 16d is configured as shown in FIGS. 6 and 7, for example. Note that in each of the control circuits shown in FIGS. 6 and 7, only the set value of the valve opening or the monitoring target of the actual valve opening position changes, and the function and operation of the steam valve control system are as follows. It is similar to that shown in FIG.

In the modification shown in FIG. 6 or 7, the position of the limit switch is set to the fully open and fully open positions of the steam valve, and the valve opening positions of the input and output on the control system are monitored. When an error occurs in the input/output corresponding to the opening position in a sequential manner, the abnormality diagnosis device 16d is configured to determine that there is a control abnormality and transmit the turbine trip signal 24.

In FIG. 6, the operating output of the fully open limit switch 26 is input to the AND circuit 29a via the NOT circuit 28a, while the operating output is obtained from the turbine rotation speed condition 22d and the converter 5, which determines whether the steam turbine is in operation. The fully open stroke position signal 30 of the operating cylinder 10 that has been
The signal is configured to be input to the circuit 29a.

On the other hand, similarly, the operating output of the fully open limit switch 27 is N
While being input to another AND circuit 29b via the OT circuit 28b, the turbine rotation speed condition 22 (jJ5 and the stroke full-open position signal 31 of the operating cylinder 10 are input to the AND circuit 29b.

AND circuits 2 for fully open position side and fully open position side
Outputs from 9a and 29b are connected to an OR circuit 32a,
When the condition of the AND circuit on either side is satisfied, the turbine trip signal 24 is configured to be transmitted if the condition continues to be satisfied until after a predetermined time set by the timer 21d.

Then, it is confirmed that the turbine is in operation according to the turbine rotation speed condition 22d, and the operation cylinder stroke full open position signal 30 becomes fully open, and if the control system is in a normal state at this time, the full open limit switch 26 also becomes fully open. , when the respective signals are transmitted to the AND circuit 29a via the NOV circuit 28a, the AND circuit 29
Condition a is not satisfied and 1;1. There is no bond output.

However, due to some malfunction, the fully open limit switch 2
6 is not fully open, each condition of the AND circuit 29a is satisfied, a signal is immediately output to the OR circuit 32a side, and the turbine trip signal 24 is transmitted.

Similarly, if the condition of the AND circuit 29b is satisfied due to some kind of malfunction in the circuit at the fully open position, the turbine trip signal 24 is transmitted.

In FIG. 7, the valve opening function full open position signal 33 and full open position signal 34 obtained from the output of the valve opening function 3 are shown instead of the full open position signal 30 and the full closed position signal 31 of the operation cylinder stroke in FIG. It is constructed using the following, and performs the same function as the modification shown in FIG.

Unlike the one in Fig. 6, which only determines abnormalities in the mechanical control system, the circuit of the abnormality diagnosis device 16d shown in Fig. 7 detects abnormalities between the systems from the electrical control system to the mechanical control system. can be judged.

According to the modification example F below, it becomes easy to detect an abnormality particularly at the time of starting the turbine and during a load drop operation from the full load point, and it becomes possible to take prompt action.

In particular, by variously changing the set values of the opening/closing positions of the steam valves to be monitored and the position detection values of the actual openings within the control system, it is possible to specify areas in which abnormalities are to be detected in a focused manner. Furthermore, since a means for safely stopping the turbine before shifting to the next operation pattern is provided, it is possible to prevent steam turbine accidents.

〔Effect of the invention〕

As explained above, according to the steam valve abnormality diagnosis device according to the present invention, when the steam turbine plant is operating normally, the valve opening of the steam valve can be set, except during transient times such as when operating conditions are changed. The signal and the actual valve opening position signal match.

Therefore, since no deviation between the two signals is detected, an abnormality in the steam valve is not diagnosed.

However, in the event of a malfunction in the operating cylinder, a broken lever, a malfunction in the oil cylinder piston, etc., the valve opening setting signal and the actual valve opening position signal take different values, and the deviation is simply a transient state. It is not temporary, but continues over a long period of time. Therefore, when the deviation continues for a predetermined period of time or more, the abnormality diagnosis device diagnoses the occurrence of an abnormality in the steam valve.

Therefore, failures occur early, restoration can be carried out quickly, and safety during operation of turbine plants and the like can be improved.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing an embodiment of the steam valve abnormality diagnosis device according to the present invention, FIGS. 2 to 4 are system diagrams showing examples of circuit configurations of the abnormality diagnosis device, and FIG. 5 is a system diagram showing an example of the circuit configuration of the abnormality diagnosis device A partial control system diagram showing a modification example of FIGS.
The figure is an electrical control system diagram of a conventional steam valve, and FIG. 9 is a mechanical control system diagram of a conventional steam valve. DESCRIPTION OF SYMBOLS 1... Steam valve, 2... Governor signal, 3... Valve opening function, 4.4a... Adder, 5... Converter, 6...
... Valve opening setting signal, 7... Actual valve opening position signal, 8.
...Amplifier, 9...Electric/hydraulic converter, 10...Operation cylinder, 11...Lever 12...Pilot valve, 13...Oil cylinder screw, 14...Orifice, 15... Lever 16° 16a, 16b, 16c,
16d... Abnormality diagnosis device, 17... Converter, Isa
, 18b...operation cylinder stroke value, 19a, 1
9b...Oil cylinder piston stroke value, 20a, 20b
, 20cm...Constant, 21a, 21b, 21c, 21d
, 21e... timer, 22a, 22b, 22c, 22
d, 22e...Turbine rotation speed condition, 23a...A
ND circuit, 24...turbine trip signal, 25a,
25b...Valve opening stroke value, 26...Full open limit switch, 27...Full open limit switch, 28
a, 28b, 28c, 28d・N07 circuit, 29a, 2
9b, 29C, 29d...AND circuit, 30...Operating cylinder full stroke position signal, 31...Operating cylinder full stroke position signal, 32a, 32b.
...OR circuit, 33...Valve opening function fully open position signal, 3
4...Valve opening function fully closed position signal.

Claims (1)

[Scope of Claims] 1. A steam valve whose position is controlled so as to eliminate the deviation between a valve opening setting signal set according to the load and rotation speed of a steam turbine and an actual valve opening position signal; A steam valve abnormality diagnostic device comprising: an abnormality diagnostic device that determines that the steam valve is abnormal when the deviation between the valve opening setting signal and the actual valve opening position signal continues for a predetermined time or more. 2. The stroke value of the operating cylinder that drives the pilot valve that supplies hydraulic oil to the oil cylinder piston for opening and closing the steam valve is used as the valve opening setting signal, while the stroke value of the oil cylinder piston is used as the actual valve opening position signal. Claim 1 characterized in that
Steam valve abnormality diagnosis device described.