JPH04315016A - Device for monitoring vibration abnormality for rotary machine - Google Patents

Abstract

PURPOSE:To reliability regarding detection of vibration abnormality of a rotary machine. CONSTITUTION:A detection signal from a pair of probes PX and PY which are mounted near guide bearings 2, 3, and 4 is inputted to a means for calculating amount of vibration state 10 through displacement meters 8 and 9, where an amount of maximum vibration amplitude of a rotary axis 1 as well as an amount of minimum gap between an amount of axis eccentricity and a guide bearing are calculated. Then, vibration abnormality is judged by comparing these operation values with a criterion reference value by using a comparator 12. At this time, a criterion reference value variable means 13 changes this criterion reference value to a proper value according to operation conditions such as a difference in water drop, etc.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention monitors abnormal vibrations of hydraulic machines such as water turbines and pump water turbines used as power generating equipment for generating electric power in hydroelectric power plants, etc., and of generators connected to these machines and operated. The present invention relates to a vibration abnormality monitoring device for rotating machinery for preventing serious accidents.

0002

[Prior Art] In recent years, hydroelectric power generation equipment has generally become faster and larger in capacity, and the hydraulic machines and generators used here, such as pump turbines and water turbines, are capable of operating at high speeds, high pressures, and under high loads. They are now exposed to harsh driving conditions. Moreover, in response to power demand, these devices are operated under various load conditions, with quick startup and shutdown, and high reliability is required for stable power supply.

[0003]Therefore, it is necessary to perform maintenance inspections reliably to prevent accidents, and in order to meet this requirement, it is common practice to periodically stop the machine and perform external inspections, non-destructive inspections, disassembly inspections, etc. However, depending on the type of abnormality, the current situation is that there is a risk that damage may occur between inspections and the next inspection, leading to serious accidents.

For this reason, in addition to the above-mentioned maintenance inspections, measures such as measuring shaft vibration during operation, monitoring the magnitude, and generating an alarm when the shaft vibration exceeds a certain level are generally taken. It has been adopted.

FIG. 9 is a schematic configuration diagram of a vertical shaft rotating machine according to such a conventional device, in which a runner 7 and a generator rotor 6, which are used both when operating a water turbine or when operating a pump, are connected to the rotating shaft. 1. This rotating shaft 1
has a total of three guide bearings, namely the upper guide bearing 2,
It is rotatably supported by a lower guide bearing 3 and a water turbine guide bearing 4. Note that 5 is a thrust bearing.

Near each of these guide bearings, a pair of non-contact shaft vibration probes (gap sensors) PX, PY are installed.
are disposed at an angle of 90° with each other, as shown in FIG.

The electrical signals from the probes PX and PY are converted into shaft vibration electrical signals as shown on the right side of FIG. 9 by a displacement meter (not shown). Then, these maximum vibration amplitudes A1, A2, A3 are measured, and when any one of them exceeds a certain value, a vibration abnormality alarm is issued.

[0008]

[Problem to be Solved by the Invention] However, rotating machinery for hydroelectric power generation is operated under various conditions, and it is difficult to accurately detect vibration abnormalities by simply monitoring the value of the maximum vibration amplitude. It was difficult.

[0009] Furthermore, when shaft vibration occurs when a machine is deteriorated or damaged, the shaft vibration generally increases as the deterioration progresses. Therefore, when monitoring abnormalities in a machine, it is considered that vibration abnormalities can be detected early by monitoring not only the magnitude of shaft vibration but also the increasing tendency thereof.

However, as mentioned above, hydraulic machines such as water turbines and pump turbines for hydroelectric power generation, and generators are operated under various load conditions depending on the power demand, and the shaft vibrations of these hydraulic machines and generators are affected by the load. conditions, water head, and pump operation,
The normal shaft vibration value differs depending on operating conditions such as power generation operation, phase adjustment operation, etc.

[0011] For this reason, the method of simply measuring the shaft vibration value and monitoring only its magnitude, as in the conventional example described above, cannot detect changes in shaft vibration due to changes in operating conditions, as well as the occurrence of abnormalities and progress of deterioration. It became difficult to distinguish this from an increase in shaft vibration, making it even more difficult to distinguish between shaft vibration abnormalities.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to accurately grasp the state of the shaft system in various operating states of rotating machinery in a hydroelectric power plant, and to quickly and quickly correct the situation when an abnormality occurs in the operating state. The object of the present invention is to provide a vibration abnormality monitoring device for rotating machinery that can reliably detect this condition and prevent serious accidents.

[0013]

[Means for Solving the Problems] As a means for solving the above-mentioned problems, the present invention provides a vibration detection means that is mounted facing a rotating shaft that is supported by a guide bearing and detects the vibration state of the rotating shaft. and, based on the detection signal from the vibration detection means, the maximum vibration amplitude amount of the rotating shaft, the amount of shaft eccentricity,
and vibration state quantity calculating means for calculating vibration state quantities such as a minimum gap amount between the guide bearing and the guide bearing, and comparing each of the calculated vibration state quantities with respective preset determination reference values. , a vibration abnormality determining means that outputs an abnormal signal when any of the vibration state quantities exceeds its determination reference value, and an alarm signal output means that outputs an alarm signal based on the abnormal signal from the vibration abnormality determining means. It has a configuration that includes the following.

[0014] Furthermore, in the above structure, the vibration abnormality determining means may further include a determination reference value variable means for changing the determination reference value in accordance with the operating conditions of the rotating machine.

[0015]

[Operation] In the above configuration, the vibration state quantity calculation means calculates, based on the detection signal from the vibration detection means, the maximum vibration amplitude of the rotating shaft, the eccentricity of the rotating shaft, and the minimum amount of eccentricity between the rotating shaft and the guide bearing. Calculate the gap amount.

The vibration abnormality determining means compares each of these vibration state quantities with its respective determination reference value, and outputs an abnormality signal when any of them exceeds the determination reference value. The alarm signal output means outputs an alarm signal based on this abnormal signal.

In this configuration, in addition to the conventionally used maximum vibration amplitude, the shaft eccentricity and minimum gap amount are also calculated, so the number of factors for determining vibration abnormality increases accordingly, and the reliability of vibration abnormality determination increases. It has a high level of quality.

Furthermore, since the vibration state of a rotating machine changes depending on the operating conditions, if the vibration abnormality determining means has a determination reference value variable means that changes the determination reference value according to the operating conditions, vibration abnormality can be detected. The reliability of the judgment becomes even higher.

[0019]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 7. FIG. 1 is a block diagram showing the configuration of this embodiment.

In this figure, a generator rotor 6 and a runner 7 are connected via a main shaft 1, and this main shaft 1 is supported by guide bearings 2, 3, and 4, respectively. At a position facing each of these guide bearings, a pair of probes PX,
A PY is provided, and its detection signal is converted into an analog electrical signal by displacement meters 8 and 9.

Based on this signal, the vibration state quantity calculation means 10 calculates the maximum vibration amplitude of the rotating shaft 1 at the position of each guide bearing, the amount of shaft eccentricity, and the minimum gap amount between the rotating shaft 1 and each guide bearing. is calculated, and the calculation result is output to the vibration abnormality determining means 11.

The vibration abnormality determining means 11 includes a comparator 12
and a judgment reference value variable means 13. Then, the judgment reference value variable means 13 changes the judgment reference value used in the comparator 12 using operating conditions such as the water head, whether the water turbine is operated or the pump is operated, and the amount of active electricity (load size) as parameters. It is designed to let you do so.

When an abnormality signal is input from the comparator 12, the alarm signal output means 14 outputs an alarm command signal to drive an alarm device, an abnormality indicator light, etc.

Note that each data from each device is stored in the recording device 1.
5, so that the state of the equipment before and after the occurrence of an abnormality can be analyzed to contribute to maintenance management.

Although not shown in FIG. 1, in reality, as shown in FIG. 2, a filter circuit 16, a DC component circuit 17, An AC component circuit 18 is provided. The analog electrical signals sent from the displacement meters 8 and 9 are filtered by this filter circuit 16 into a DC component and an AC component (the signal component used in conventional shaft vibration monitoring is this AC component called "shaft vibration"). ) and are outputted to the vibration state quantity calculating means 10 via a DC component circuit 17 and an AC component circuit 18, respectively.

Next, the operation of this embodiment configured as described above will be explained. For example, unbalanced force generated in the runner 7, damage to the runner 7 itself, damage to the guide bearings 2, 3, and 4, bending of the rotating shaft 1, abnormal magnetic force generated in the rotating electric machine,
Or, due to the movement of the entire building that makes up the hydroelectric power generation equipment, the inclination of the building (in fact, there are cases where the movement of the axis of the guide bearing was measured due to seasonal changes), etc. Suppose that an abnormality occurs in shaft vibration.

In this case, the Lissajous waveform corresponding to each guide bearing is not a perfect circle, but a distorted saw-shaped circle, as shown on the right side of FIG. Note that the Lissajous waveform is a waveform that shows the locus of shaft vibration, and it is obtained by combining the shaft vibration output signals of displacement meters 8 and 9, and is commonly used as a technology for shaft vibration detection. It is something.

Further, as described above, from each analog electrical signal from the displacement meters 8 and 9, a waveform in which a DC component and an AC component are combined as shown in FIG. 4 is obtained. and,
The filter circuit 16 described above can separate this waveform into a DC component waveform as shown in FIG. 5 and an AC component waveform as shown in FIG.

FIG. 3 is an enlarged view of the Lissajous waveform shown in FIG. In this figure, the position of the shaft rotation center (axis center) is (X0, Y0), and the values of X0 and Y0 can be obtained from the waveform of FIG.

[0030] Therefore, if the distance from the origin of this shaft center position, that is, the amount of shaft eccentricity, is H, then this H is

0031
]

It can be obtained by [Equation 1]. Also, the direction θ of the axis at this time
teeth,

[0032]

[Math 2] It can be found by

[0033] Then, the shaft vibration amplitude in the axial direction is expressed as W
The value of is obtained from the waveform in Fig. 6, so if the diameter of the guide bearing is D, the minimum gap amount δmin is

0034
]

[Math 3] It can be found by

Furthermore, the maximum shaft vibration amplitude A can also be determined from the waveform shown in FIG. 6 in the same way as the shaft vibration amplitude W.

In this way, the vibration state quantity calculation means 10 calculates the shaft eccentricity H, the axial direction θ, and the minimum gap amount δmin.
, calculates the maximum vibration amplitude amount A, and outputs the calculation result to the comparator 12 of the vibration abnormality determining means 11.

The comparator 12 compares this calculation result with the judgment reference value from the judgment reference value variable means 13, and when any of the vibration state quantities exceeds the judgment reference value, an abnormality is sent to the alarm signal output means 14. Output a signal.

At this time, as mentioned above, signals related to operating conditions such as water head are inputted to the judgment reference value variable means 13, and the judgment reference value variable means 13 adjusts the most suitable signal according to these operating conditions. The criterion value is changed to an appropriate value. Therefore, the vibration abnormality determination means 11 can always accurately determine abnormality in shaft vibration regardless of differences in operating conditions.

In this way, in the apparatus shown in FIG. 1, since the vibration state quantities, which are three types of physical quantities, are calculated for each of the three guide bearings, abnormalities are determined based only on the maximum vibration amplitude. It is more reliable than conventional equipment.

[0040] Furthermore, when an abnormality in shaft vibration occurs during operation, a large change usually occurs first in the vibration state quantity of the guide bearing closest to the place where the abnormality has occurred; In most cases, this applies to the entire shaft system, so there is no practical problem in determining that there is an abnormality when any vibration state quantity exceeds the determination reference value. Therefore, abnormalities in shaft vibration can be detected quickly.

In the above embodiment, the number of guide bearings is three, but of course this number can be changed to any number.

Further, in the above embodiment, the case of a vertical shaft rotating machine has been explained, but the present invention is also applicable to a horizontal shaft rotating machine.

[0043]

As described above, according to the present invention, not only the maximum vibration amplitude of the rotating shaft but also the shaft eccentricity and the minimum gap between it and the guide bearing are calculated, and the calculation results Since the configuration is such that the values are compared with respective determination reference values, vibration abnormalities in the shaft system can be detected quickly and reliably.

[0044] Furthermore, if the determination reference value is configured to be changed to the most appropriate value depending on the operating conditions, the reliability of determining vibration abnormality can be further improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a detailed configuration of a part of FIG. 1;

FIG. 3 is an explanatory diagram of the operation of FIG. 1;

FIG. 4 is a waveform diagram for explaining the operation of FIG. 1;

FIG. 5 is an explanatory diagram of the operation of FIG. 1;

FIG. 6 is an explanatory diagram of the operation of FIG. 1;

FIG. 7 is an explanatory diagram of the operation of FIG. 1;

FIG. 8 is an explanatory diagram of the prior art.

FIG. 9 is an explanatory diagram of the prior art.

[Explanation of symbols]

1 Rotation axis 2 Guide bearing 3 Guide bearing 4 Guide bearing 10 Vibration state quantity calculation means 11 Vibration abnormality determination means 13 Judgment reference value variable means 14 Alarm signal output means PX Vibration detection means (probe) PY Vibration detection means (probe)

Claims (2)

[Claims] 1. Vibration detecting means mounted facing a rotating shaft supported by a guide bearing and detecting the vibration state of the rotating shaft; a vibration state quantity calculation means for calculating vibration state quantities such as a maximum vibration amplitude amount, a shaft eccentricity amount, and a minimum gap amount between the guide bearing and the vibration state quantity, and preset each of the calculated vibration state quantities. vibration abnormality determination means for comparing with each determination reference value and outputting an abnormal signal when any vibration state quantity exceeds the determination reference value; A vibration abnormality monitoring device for a rotating machine, comprising: an alarm signal output means for outputting an alarm signal. 2. The vibration abnormality monitoring device for a rotating machine according to claim 1, wherein the vibration abnormality determining means has a judgment reference value variable means for changing the judgment reference value according to the operating conditions of the rotating machine.