JPH0460176A - Device for detecting abnormality of vertical shaft hydraulic machine - Google Patents

Abstract

PURPOSE:To accurately detect abnormality due to eccentricity of a main shaft by obtaining a deformation mode curve of (n-1) order in an axial direction based on (n) number of eccentric distance data and discriminating the abnormality in the case of a deviation between a clearance in a predetermined location and a deformation mode interpolation value smaller than a preset permissible value. CONSTITUTION:A water turbine main shaft 20 is rotatably supported in three parts. An eccentric distance between shaft center positions of the water turbine main shaft at its stationary and rotational time is detected by position detecting sensors 1 to 3 arranged in the vicinity of each bearing 23 to 25. In this arithmetic part 5, eccentric coordinates (Xi, Yi), in which the shaft center position of the water turbine main shaft at stationary time in a plane at a right angle with the axial direction in a position Zi of each position sensor serves as an original point, are calculated and also interpolating a coordinate data in a Z axis direction based on Xi, Yi to set X and Y direction deformation mode curves shown by a secondary curve. The eccentric distance in an arbitrary position in the axial direction of the water turbine main shaft 20 is calculated by these deformation mode curves and compared with a permissible value to discriminate abnormality by a discriminating part 9 from the eccentric coordinate data.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Field of Application) The present invention relates to an abnormality detection device for vertical shaft hydraulic machines, and in particular, the present invention relates to an abnormality detection device for vertical shaft hydraulic machines, particularly when the clearance with a bearing becomes insufficient due to shaft runout during rotation of the main shaft of a water turbine. The present invention relates to an abnormality detection device for a vertical shaft hydraulic machine that detects an abnormality when an abnormality occurs.

(Prior Art) Generally, the main shaft of a water turbine in a vertical shaft hydraulic machine is supported by a plurality of guide bearings, and a predetermined clearance is set between the main shaft of the water turbine and the guide bearings to prevent wear due to contact. ing. For this reason, it is known that the main shaft of the water turbine causes minute shaft runout when rotating. If this shaft runout becomes excessive, there is a risk of bearing burnout or seal damage, so this type of vertical shaft hydraulic machinery is equipped with a device that detects abnormalities in the bearings, etc. when the main shaft of the water turbine rotates. There is.

FIGS. 5(a) and 5(b) show an example of a conventional abnormality detection device for a vertical shaft hydraulic machine.

In FIG. 5(a), reference numeral 20 indicates a main shaft of the water turbine, and a runner 21 is fixed to the lower end of the main shaft 20 of the water turbine. A rotational force is generated in the runner 21 by the flowing water flowing from the flow path 22, and the water turbine main shaft 20 can be rotated at a predetermined speed. At this time, the water turbine main shaft 2
0 is the upper bearing 23, the lower bearing 24, and the water turbine bearing 25.
The water turbine main shaft 20 and each bearing 23 are
．． 24. There is a small clearance 2 of a predetermined size between 25 and 24.
3a, 24a, and 25a are formed. Further, a shaft seal portion 27 is protruded on the upper cover 26 directly above the runner 21, and this shaft seal portion 27 and the water turbine main shaft 2
A minute clearance 27a is also formed between 0 and 0. Furthermore, a runner band 21 at an outer peripheral position of the runner 21
There is also a small gap 28a between the lower cover 28 and the lower cover 28.

On the other hand, a generator rotor 29 is fitted onto the upper part of the water turbine main shaft 20. The generator rotor 29 has a considerable weight and generates a large rotational inertia force and unbalanced force in the horizontal direction when rotating. This rotational inertia force and unbalance force act on the bearing portion and the seal portion as a horizontal force, causing the water turbine main shaft to oscillate.

For this reason, in order to prevent the shaft runout of the main shaft of the water turbine from becoming excessive, a plurality of gap detection sensors 30, 30, etc. are usually arranged near the bearing as shown in Fig. 5(b), and the eccentricity at each position is The amount of shaft runout during rotation is monitored.

The amount of shaft runout is detected as a continuous waveform as shown in FIG. 5(b), and an abnormality is determined when this value becomes larger than a set allowable value.

In addition, as shown in FIG. 6, the gap detection sensors 30, 30,
There are also anomaly detection devices equipped with...

According to this device, the amount of eccentricity at the position can be accurately monitored.

(Problem to be solved by the invention) However, the above-mentioned abnormality detection device has a limited range of monitoring, and in areas where the amount of shaft runout cannot be detected, bearing burnout, contact between the water turbine main shaft and the seal part, etc. There is a possibility that this may occur.

Also, if the above-mentioned gap detection sensor is placed in the bearing part or seal part, the above-mentioned problem can be solved, or the above-mentioned bearing part and seal part are generally exposed to high temperature and pressure, and there is a risk of foreign matter getting mixed in. The sensor is easily damaged or malfunctions, making it difficult to continue stable state monitoring over a long period of time. Furthermore, gap detection sensors must be placed in advance for all parts to be monitored, and in this case, it is difficult to newly provide monitoring parts.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the problems of the conventional technology described above, and to provide a vertical shaft that can approximately calculate the gap amount at any position in the axial direction of the main shaft of a water turbine and grasp the eccentric state at that position. An object of the present invention is to provide an abnormality detection device for hydraulic machinery.

[Structure of the invention]

(Means for Solving the Problem) In order to achieve the above object, an interval is provided in the axial direction of the water turbine main shaft to detect the eccentric distance between the shaft center position when the water turbine main shaft is at rest and the shaft center position when the water turbine main shaft is rotating. The n position detection means provided in a deformation mode interpolation means for approximating the deformation mode interpolation value, and a deviation determination means for calculating the deviation between the clearance at a predetermined position of the main shaft of the water turbine and the deformation mode interpolation value, and determining an abnormality when this deviation is smaller than a set tolerance value. It is characterized by the fact that it is equipped with

(Function) According to the present invention, the eccentric distance between the shaft center position of the water turbine main shaft when it is at rest and the shaft center position when it is rotating is determined by the n position detection means provided at intervals in the axial direction of the water turbine main shaft. is detected, and the n eccentricity distance data obtained by the position detection means are interpolated in the axial direction by the deformation mode interpolation means to approximate the axial deformation mode of the water turbine main shaft with an (n-1)th order curve. The deviation determination means calculates the deviation between the clearance at a predetermined position of the water turbine main shaft and the deformation mode interpolated value, and if this deviation is smaller than the set tolerance value, an abnormality is determined. It is possible to detect the eccentricity distance at any position where the direction of rotation is desired to be monitored, and it is possible to accurately grasp the eccentricity state of bearings and seals where the amount of eccentricity cannot be directly detected.

(Embodiment) An embodiment of the abnormality detection device for a vertical shaft hydraulic machine according to the present invention will be described below with reference to FIGS. 1 and 2. In this embodiment, three position sensors are provided in the axial direction of the main shaft of the water turbine.

Hereinafter, structures equivalent to those of the conventional example shown in FIG. 5 will be described using the same reference numerals.

In FIG. 1, reference numeral 20 indicates a main shaft of a water turbine, and a runner 2 is fixed to the lower end of the main shaft 20 of the water turbine. This water turbine main shaft 20 has a two-part bearing 23 and a lower bearing 2.
4 and a water wheel bearing 25, and minute clearances 23a, 24a, and 25a of predetermined dimensions are formed between the water wheel main shaft 21 and each bearing 23, 24, and 25. Furthermore, a position detection sensor 2.3 is arranged near the bearings 23, 24, and 25, and the installation height of this position sensor 2.3 is based on the horizontal center line position 4 of the runner 21. It is determined in the axial direction (Z-axis direction coordinate Z, (i = 1 to 3) of the main shaft of the water turbine set as the horizontal reference line. Also, the position sensor 2.3 is determined at the upper J self-installation height. It is possible to detect the eccentric distance between the shaft center position when the main shaft of the water turbine is stationary and the shaft center position when rotating.Furthermore, the position sensor 2.3 is connected to the calculation section 5.This calculation section 5 As shown in Figure 1, the eccentric coordinates (X,, Y,) with the axial center position of the main shaft of the water turbine at rest in a plane perpendicular to the above-mentioned axial direction at the position Z of each position sensor as the origin is calculated.

In addition, in the figure, the circle centered on the above-mentioned origin shown together with the (X, Y,) coordinates indicates the amount of clearance at each location. Furthermore, in the arithmetic unit 5, -LJX,
Interpolate the coordinate data in the Z-axis direction based on (i=]~3), Y, and (i=1~3) [7, the following quadratic curve X=a Z2+b Z+c X X XY-a
An X-direction deformation mode curve and a Y-direction deformation mode curve expressed as Z2+b Z+c y y y are set.

In Fig. 1, reference numeral 6 indicates an X-direction deformation mode curve schematically superimposed on the main shaft of the water turbine, and in Fig. 2, reference numeral 7 indicates an X-direction deformation mode curve, and reference numeral 8 indicates a Y-direction deformation mode. It shows a curve.

This X-direction deformation mode curve 7 and Y-direction deformation mode curve 8
Accordingly, the eccentric distance at any position in the axial direction of the main shaft of the water turbine can be approximately calculated.

That is, the eccentric coordinates A (X

Y), B(X6.Y,)・ can be obtained, and this eccentric coordinate data is output to the discrimination section 9. At this time, the discrimination unit 9 has the clearance mδ8 of each of the above parts,
δb... or S is remembered.

In addition, this clearance amount is shown in Figures 1 and 2.
Its size is displayed as a circle centered at the axis position.

As a preprocess, the discrimination section 9 calculates the deviations ea, eb, etc. at each position from the eccentric coordinates and clearance amount of each part using the following formula.

e = δ-J-7-2. V 2 aa aa Further determined deviations e, ', e b... and the discrimination section 9
Tolerance values ε, εb, etc., which are preliminarily set, are compared, and if the deviation is smaller than the tolerance, an abnormality is determined.

FIG. 3 shows another embodiment in which n position sensors are provided in the axial direction of the main shaft of the water turbine. At this time, in the arithmetic unit 5, the above Xi (i=1 to n
) and Yi (i-1 to n), respectively, and interpolate the coordinate data in the Z-axis direction to form the following <n-1)-order curve
Z+(]X
X XY-a Z 10b
Zn-2+-+c Ztendy y
An X-direction deformation mode curve 11 and a Y-direction deformation mode curve 12 represented by yy are set.

Next, by performing the above-described discrimination processing in the discriminator 9 using the deformation mode curve, it becomes possible to detect the eccentric state with even higher accuracy.

In addition, in this embodiment, the eccentricity coordinates (X, , Y,
), or the eccentric coordinates (X,, Y,) can be directly detected by installing two gap sensors 13, 13 at right angles as shown in Fig. 4. .

〔Effect of the invention〕

As is clear from the above description, according to the present invention, the eccentric distance of the shaft center during rotation of the water turbine main shaft is detected by n position detection means provided at intervals in the axial direction of the water turbine main shaft,
Using the deformation mode interpolation means, a (n-1)th deformation mode curve is determined in the axial direction based on the n eccentricity distance data, and
The deviation determination means calculates the deviation between the clearance of a predetermined part and the deformation mode interpolated value, and when this deviation is smaller than the set tolerance value, an abnormality is determined. It is possible to accurately detect abnormalities due to eccentricity of the spindle by calculating the eccentricity state, and it is also possible to continue stable status monitoring over a long period of time without installing the position detection means in a harsh environment. be effective.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the state of detection of deviation of the main shaft of a water turbine by an embodiment of the abnormality detection device for vertical shaft hydraulic machines according to the present invention, and FIG. FIG. 3 is an explanatory diagram of the X-direction deformation mode curve and the X-direction deformation mode curve. FIG. 4 is a plan view showing an embodiment of the position sensor according to the present invention, and FIGS. 5 and 6 are front views showing an example of a conventional abnormality detection device for a vertical shaft hydraulic machine. 1.2.3...Position sensor, 5...Calculation unit, 6.7
．． 11...X direction deformation mode curve, 8.12...X
Directional deformation mode curve, 9... Discrimination unit, 13... Gap sensor. 7 (quadratic curve) Figure 1 Figure 7

Claims (1)

[Claims] n position detection means provided at intervals in the axial direction of the water turbine main shaft for detecting the eccentric distance between the shaft center position of the water turbine main shaft when it is stationary and the shaft center position when it is rotating; a deformation mode interpolation means for interpolating the obtained n pieces of eccentricity distance data in the axial direction and approximating the axial deformation mode of the water turbine main shaft with an (n-1) order curve; An abnormality detection device for a vertical shaft hydraulic machine, comprising: deviation determining means for calculating a deviation between the clearance and the deformation mode interpolated value, and determining an abnormality when this deviation is smaller than a set tolerance value.