JPS5813725B2 - Turbine hinges - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a turbine valve control device, and more particularly to a turbine valve test method for checking that there is no abnormality in the turbine valve control device.

Turbines, especially large-capacity turbines for power plants, are often operated at a constant turbine output.

In this case, since the opening degree of the turbine control valve is almost at a constant position, it is thought that even if an abnormality such as mechanical wear occurs, it cannot be detected, and therefore, conventionally, valve tests are often performed.

However, the conventional method of valve testing involves operating the valve from fully open to fully closed, and confirming that there are no abnormalities when the valve reaches the fully closed position, which has the drawback of significantly reducing turbine output.

SUMMARY OF THE INVENTION An object of the present invention is to provide a valve testing method that can check for abnormalities while minimizing a decrease in turbine output during a valve test.

This invention narrows the valve opening/closing range during a valve test, and determines whether there is any abnormality based on the deviation between the target valve opening and the valve opening.

As shown in FIG. 1, when the target valve opening Pr is given,
Since the contact X is open during normal operation, the target Pr passes through the comparator 1 and is transmitted to the comparator 2 as a negative signal.

The comparator 2 detects the valve opening P detected by the valve opening detector 5.
a and obtain the deviation ε (ε=Pr=Pa).

The deviation ε is amplified by the amplifier 3 of the valve drive unit 150, and further converted into a hydraulic signal by the electro-hydraulic converter 4 to open and close the control valve 7.

Changes in the opening degree of the control valve 7 are detected by the detector 5 and fed back, and the valve opening degree Pa is controlled to match the target valve opening degree pr.

When performing a valve test, when the SW is turned on, relay X is energized and contact X is closed.

When the contact X closes, a valve test signal T obtained by dividing the power supply voltage by resistors 8 and 9 is sent to the comparator 1.

The comparator 1 compares it with the target valve opening Pr, and outputs the test target valve opening Ps (Ps=Pr-T).

Furthermore, the target valve opening degree Ps for dest is determined by the comparator 2 as the valve opening degree Pa.
The deviation, (ε=p3-pa) is obtained, and the valve opening degree P
The control valve 7 is adjusted so that a matches the test target valve opening Ps.
is operated closed.

If an abnormality occurs at this time, the control valve will not be closed.
The deviation ε no longer becomes small.

This phenomenon in which the deviation ε does not become smaller is detected by the signal discriminator 6, and the relay Y is energized.

When relay Y operates, contact Y closes and timer relay T, which instantaneously returns to the time-limited operation, is energized, and after a certain period of time, relay Z is energized to issue an alarm.

The reason why the timer relay T is provided is to prevent an alarm from being generated when the valve is opened or closed during normal operation.

If the valve test is performed using the method described above, the range in which the valve is closed can be narrowed, and the decrease in turbine output can be reduced.

FIG. 2 shows another embodiment of the invention.

Figure 2 is a modified diagram especially when there are multiple control valves.
The difference from FIG. 1 is that the valve test signal T is applied to the other valves with the sign reversed.

FIG. 2 is a diagram showing a valve test method for the control valve 71.

When a valve test is performed in the same manner as in FIG. 1, a valve test signal T is applied to the comparator 11, and the control valve 71 is closed.

On the other hand, since the valve test signal T is applied to the comparator 12 with a different sign, the control valve 72 performs an opening operation in the opposite direction, and the control valve 72 compensates for the turbine output that has slightly decreased due to the control valve 71, and the valve test signal T is applied to the comparator 12. It is possible to completely eliminate any influence on turbine output due to

FIG. 3 is a further modified view of FIG. 2.

Normally, in order to improve the controllability of the turbine output, the target valve opening Pr is often corrected by a signal Rf corresponding to the turbine output (in most cases, a pressure signal after the first stage of the turbine).

FIG. 3 shows an example in which the present invention is applied to such a case.

The target valve opening Pr is compared with the output equivalent signal Pf by the comparator 110, the difference is multiplied by K by the coefficient unit 130, and the comparator 120? It is compared with the target valve opening Pr again to obtain a corrected target valve opening Pr'.

The detailed operation of this correction section will be omitted, but even if the output fluctuates due to some valve operation, the output can be maintained at the predetermined target opening degree Pr by feedback of the output equivalent signal Pf. It is a characteristic.

When a valve test is performed, contacts X2 and X4 open, and contacts X1 and X4 open.
X3 closes.

By opening the contact x4, the corrected target valve opening P'r immediately before the start of the valve test is stored in the analog memory 140, and this value P'ro is stored in the analog memory 140 until the test is completed.
It is output from 40.

By opening contact X2 and closing contact X3, P'ro is sent to comparator 11 instead of P'r, while by closing contact X1, test signal T is applied to comparator 11.

The comparator 11 compares the two signals P'r6gT, and the control valve 71 performs a closing operation as in FIG.

However, in the case of Fig. 3, since the output is corrected, the output that slightly decreased to the control valve 71 is compensated for by increasing P'r by the correction section and opening the control valve 72, and the output fluctuation is The valve test can be carried out without any problems occurring.

Although FIGS. 1, 2, and 3 have been described above with analog control in mind, the present invention can be applied in exactly the same way even when a digital computer is used.

FIG. 4 shows a flowchart when applied to a digital computer.

FIG. 4 is a flowchart of the valve test section of FIG. 3.

Here, Ps is a signal corresponding to the output of the comparator 11 in FIG. be.

When you start the valve test, the flow shown in Figure 4 starts, and first,
Valve test to determine whether.

If it is not a valve test, this flow will not be executed and will end.
If it is a valve test, proceed to the next step.

Next, calculate Ps between the corrected target opening P'r and the test signal T before starting the test, and further calculate Ps and the valve opening Pan.
The deviation εn from the valve is determined, and if εn is larger than the specified value εa, it is regarded as abnormal, and if this abnormal state continues for a specified number of times m (specified time), a valve abnormality alarm is issued.

Further, if εn is smaller than εa or εn is larger than εa less than m times, it is determined that the valve is normal and no alarm is issued.

Finally, according to the deviation εn, the valve drive signal Dn is set as Dn=f(ε
n), and the flow of the valve test ends.

The contents of this flowchart are the same as the example shown in FIG.

According to this invention, when performing a valve test, it is possible to determine whether the control valve is normal or abnormal by closing and opening it within a narrow range, so it is possible to extremely reduce the turbine output during the valve test, and it is possible to prevent disturbances in the output. This has the effect of making it possible to inspect the valve without having to give it any damage.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment to which this invention is applied, Figs. 2 and 3 are block diagrams showing other embodiments, and Fig. 4 is a block diagram showing another embodiment.
The figure is a flowchart showing another embodiment. Explanation of symbols, 1, 2... Comparator, 3... Amplifier, 5...
Valve opening degree detector, 6... Signal discriminator, 7... Control valve.

Claims (1)

[Claims] 1. In a Kubin valve control device that has a drive unit that obtains the deviation between the target well opening and the valve opening and opens and closes the turbine control valve to reduce this valve opening deviation, a valve test is performed to the target valve opening. A turbine valve control device that detects an abnormality based on the level of valve opening deviation by applying a signal.