JPS5819144A - Vibration diagnosing device for rotary machine - Google Patents

Abstract

PURPOSE:To improve the reliability of a vibration diagnosing device by providing an axial vibration signal to be inputted and means for diagnosing a malfunction of a rotating speed signal in a device for diagnosing a malfunction from the axial vibration signal and the speed signal, thereby eliminating an erroneous operation due to an abnormal input signal. CONSTITUTION:In a device for diagnosing the malfunction of a rotary machine by inputting an axial vibration signal detected by a vibration meter 7 and a rotating speed signal detected by a rotation detector 13 to a control arithmetic unit 10, a signal malfunction discriminating and processing unit 12 is mounted on the arithmetic unit 10, thereby judging the malfunction of the axial vibration signal and the speed signal. A signal including its noise is cut when the malfunction of the input signal is temporary, and the arithmetic unit 10 is operated, and an ordinary malfunctionis judged as a defect of each detecting means 7 or 13 and is indicated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibration diagnosis device for rotating machines such as steam turbines and generators in a power generation plant.

Recent trends in thermal and nuclear power plants are increasing in capacity, and the reliability of rotating machines such as turbines and generators, which are their main equipment, is required to be further improved. A device that automatically monitors and diagnoses has been proposed.

Abnormalities in rotating machines often appear in shaft vibrations, so by monitoring shaft vibrations, most of the abnormalities in rotating machines can be detected. By the way, recent diagnostic equipment is automated, and if the vibration sensor correctly detects shaft vibration, 1 if not detected or if the noise signal included in the vibration data is incorrectly processed.
The diagnostic equipment malfunctions.

There is a risk that correct diagnostic results may not be obtained. Therefore, in such automated diagnostic equipment.

It has become necessary to take measures against abnormalities in processing signal data.

The present invention was made in view of this prefecture, and its purpose is to provide a highly reliable vibration diagnosis device for rotating machines that can always perform correct diagnosis without malfunctioning even when an abnormal detection signal is input. is to provide.

In order to achieve this object, 1. the present invention determines whether an input detection signal is abnormal or not, and when it is determined that it is abnormal, whether it is due to temporary noise or 1. a failure of the diagnostic device; It is characterized by determining.

Hereinafter, the present invention will be explained in detail based on examples.

In FIG. 1, numerals 1 to 3 are rotors of a turbine.

Reference numeral 4 denotes a rotor of the generator, and these rotors 1 to 4 are interconnected to constitute a rotating shaft system of the turbine and the generator. Reference numeral 5 denotes a bearing that supports a rotating shaft system. Zero-axis vibration is detected by a vibration pickup 6 at the journal portion of the bearing 5. The output signal of the vibration pickup 6 is input to the vibration meter 7.

further converted into an electrical signal proportional to the vibration amplitude.

This result is input into multiple data input device 8.

This multiple data input device 8 is comprised of a sample hold circuit for simultaneously capturing analog vibration signals from multiple points of the vibration meter 7, and a filter for removing unnecessary frequency components during signal capture. Multiple data input device 8
The vibration signal output from the controller is digitized by an A/D converter 9 and input to a control arithmetic unit 10.

On the other hand, the rotation signal of the rotating shaft system detected by the one-rotation detector 13 is amplified and digitized by the tachometer 14, and then input to the control calculation device 10.

The control calculation device 10 determines the relationship between the number of rotations and the vibration amplitude based on the vibration signal input from the vibration pickup 6 and the rotation number signal at the time of acquisition. The overall amplitude of the vibration signal including all frequency components is determined by the control arithmetic unit 10.

Furthermore, a frequency component that matches the rotational speed, that is, a rotational synchronous component, is extracted, and these overall amplitudes and rotational synchronous components are used for vibration diagnosis.

The vibration data is compared with a determination level stored in advance in the control arithmetic unit 10 to determine whether there is an abnormality in the vibration of the one-rotation machine. That is, if the vibration value is below the permissible level, it is determined to be normal, and if it exceeds the permissible level, it is determined to be abnormal. The diagnostic results executed in this way are displayed on the display device 1.
The vibration signal from the vibration pickup 6 and the rotation speed signal from the rotation detector 13 input to the control calculation device IO are as follows.
The signal is sent to the signal abnormality determination processing device 12.

6. The presence or absence of signal abnormality can be checked. First, it is determined whether there is a temporary abnormality in the signal. This is to prevent the negative effects of intermittent noise entering the measurement circuit. In this case, temporary abnormal data is removed and the results are used for vibration diagnosis in the control calculation unit 10. Use as data.

Next, the signal abnormality determination processing device 12 is a measurement system.

That is, abnormalities in the rotation speed and vibration data due to defects in sensors, wiring, measuring instruments, etc. are determined.

For this purpose, a vibration diagnosis range regarding the number of revolutions and vibration amplitude is determined, and if data outside this range is obtained,
It is determined that there is a failure in the sensor, wiring, measuring instrument, etc. ◇In other words, if it is smaller than the lower limit of the vibration diagnosis range or larger than the upper limit, it is determined that there is an abnormality in the measurement system and the result is displayed. It is displayed on the device 11. When the rotation speed data and vibration data fall within the vibration diagnosis range, the vibration diagnosis is performed using these data.

When analyzing the measured data of shaft vibration of steam turbines and generators at power plants, there was intermittent noise in the 1 rotation speed multiple, and due to this effect, the correct rotation speed could not be obtained0Such a case for.

An abnormality occurs temporarily, but then it returns to normal. Such temporary anomalies in signal data.

0, which can be determined by comparing a single signal with the average value of several previous input signals.

If the difference between the two is large, it may be determined that the single signal contains an erroneous signal due to noise.

If such a temporary abnormality in signal data occurs, the single signal containing noise is ignored and the signal is re-inputted to continue diagnosis.

Examples of electrical signal abnormalities caused by failures in the diagnostic device include noise generation due to defective wiring, loss of signal due to contact failure or disconnection, noise generation due to sensor failure, and the like. If an abnormality occurs in the 1-revolution meter circuit, the rotation speed data becomes abnormal, and if an abnormality occurs in the vibration meter circuit, the vibration amplitude data becomes abnormal.

A signal abnormality caused by an abnormality in the diagnostic device will be explained with reference to FIG. Abnormality in the tachometer system (A.

When the range A') occurs, the value of the number of revolutions per rotation becomes abnormally small or large. The operating range C of the rotating body is fixed, and if rotation speed data exceeding this operating range C is obtained (A'), the 1-tachometer system is often malfunctioning, and the 0 rotation speed is abnormal. An example of (A) where the number of revolutions per revolution is abnormally large is a faulty contact or a break in a part of the wiring.・Examples of abnormally small vibration amplitude being measured (B) include poor contact or disconnection in the measurement circuit, failure of the vibration meter, etc.
An example (B') in which the vibration amplitude is measured to be abnormally large is when electrical noise due to poor wiring is measured.

In this way, the abnormality judgment for the input signal is performed.

When an abnormal signal is detected, it is determined whether it is caused by temporary noise or a failure of the diagnostic device 1, which improves the reliability of the diagnostic device and improves the safety of the rotating machine. As explained above, according to the present invention, abnormalities in input shaft vibration signals and rotational speed signals are determined as part of the diagnostic function of the diagnostic device, so malfunctions due to signal abnormalities can be prevented. This allows accurate diagnosis to be made at all times.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a vibration diagnostic device for a rotating machine according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram for explaining an abnormality in a vibration signal caused by an abnormality in the diagnostic device. 6... Vibration pickup, 7... Vibration meter, 8...
Multiple data input device, 9... A/D converter, 10...
- Control calculation device, 12... Signal abnormality determination processing device, 1
3...Second U number◆

Claims (1)

[Claims] 1.Equipped with a means for detecting the shaft vibration of a rotating machine, a means for detecting the rotation speed of the rotating machine, and a means for diagnosing the presence or absence of an abnormality in the rotating machine from the detected shaft vibration signal and rotation speed signal. A vibration diagnosing device for a rotating machine, comprising means for determining whether or not the shaft vibration signal and rotation speed signal input to the diagnostic means are abnormal.