JPS6153464A - Runner gap monitor for hydraulic turbine - Google Patents

Abstract

PURPOSE:To make a runner gap monitorable directly and continuously, by installing plural displacement sensors, detecting a distance of up to a movable runner vane, so as to be opposed to a tip end of the movable runner vane of a hydraulic turbine, while monitoring the runner gap according to the output. CONSTITUTION:A runner 1 in this hydraulic turbine is made up of attached plural runner vanes to a runner boss 3, while each of these runner vanes 2 is designed so as to make its tilting angle alterable by means of a driving mechanism built in the runner boss 3. In this case, each of displacement type or overcurrent type first and second displacement sensors 6 and 7 is secured to a turbine casing 4 housing the said runner 1 in a way of being opposed to a tip end 2a of the runner vane 2. In addition, a position sensor 8 detecting a rotation position of these runner vanes 2 is set up and an around a shaft 1a of the runner 1. Then, from each output of each of sensors 6-8, a signal 9a corresponding to the maximum displacement of the runner vane tip end 2a is outputted out of an arithmetic unit 9 and displayed on a displayer 11.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a Kabran water turbine with movable runner vanes,
The present invention relates to a device that continuously detects a gap between a runner vane and a water turbine casing of a mixed flow water turbine, a cylindrical water turbine, etc. during operation of a water turbine, and particularly relates to a configuration that directly detects the gap in a non-contact manner.

[Prior art and its problems]

In the above-mentioned water turbine, when the gap between the runner vane and the turbine casing increases, the amount of water passing through the turbine without doing any work on the runner vanes increases and the efficiency of the turbine decreases. Therefore, the gap heat is kept as short as possible. Efforts are being made to do this, but on the other hand, there is a risk that an accident may occur where the runner vane (hereinafter also simply referred to as vane) comes into contact with the turbine casing for the reasons explained below.

(1) The vane drive tower installed in the runner boss is damaged as a result of vane drive operations that are frequently performed during turbine operation, causing the vanes to protrude outward.

(2) The vane is deformed by external force due to centrifugal force or water flow, and the tip of the vane protrudes outward.

(3) When the water turbine is brought to an emergency stop, the runner also vibrates in a direction perpendicular to the axis of the runner.

(4) The generator connected to the shaft of the water turbine and said shaft are integrally covered with a valve casing, and this integrated structure is supported by the water turbine stay vanes. The runner axis is displaced in a direction perpendicular to the runner axis.

Therefore, in the above-mentioned water turbines, it is necessary to constantly detect and monitor the gap between the vane tip and the water turbine casing.For this reason, conventionally, vibrations of the turbine shaft and bearings were observed and the gap between the vane tip and the water turbine cage was measured. The gap condition is detected only after an accident occurs, and the size of the gap cannot be detected, so knowing the size of the gap makes it impossible to operate the water turbine efficiently. There is a problem.

[Purpose of the invention]

The present invention solves the problems of the conventional monitoring device that monitors the gap between the tip of a water turbine vane and the water turbine casing, as described above, and monitors the size of the gap directly and non-contactly and continuously. The purpose of the present invention is to provide a water turbine runner gap monitoring device that can detect the runner gap of a water turbine.

[Key points of the invention]

In order to achieve the above-mentioned object, the present invention provides a plurality of movable runner vane-equipped water turbines, each of which has a movable runner vane, and which outputs a signal corresponding to the size of the gap between the runner vane tip and the tip of the runner vane. The displacement sensors are fixed to the water turbine casing, and an arithmetic circuit is provided to which each output signal of these displacement sensors is input, and the arithmetic circuit outputs a signal corresponding to the maximum displacement of the tip of the runner vane. A water turbine runner gap monitoring device that monitors the gap and can directly and continuously detect the size of the gap is provided.

[Embodiments of the invention]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention. In the figure, 1 is a water turbine runner in which five runner vanes 2 are attached to a runner post 3, and the runner vanes 2 are incorporated in the runner boss 3. It is configured so that the inclination can be changed by a drive mechanism.

4 is a water turbine casing in which the runner 1 is housed, 2a is the tip of the runner vane 2, 5 is the gap between the tip 2a and the inner surface of the casing 4, and δ is the size thereof. 6.7 respectively penetrate through the casing 4.
First and second displacement sensors 8 of capacitance or current type are fixed fluid-tightly to the runner 1 and output the cage signals 5a, 7a according to δ. axis 1
A position sensor detects the rotational position of the runner vane 2 through the rotational position of a, 8a is its output signal, 9 is the signal 6a
, 7a, and 8a are inputted to it, and outputs a signal 9ai corresponding to the maximum displacement of the runner vane tip 2a. Reference numeral 10 denotes a water turbine launch gap monitoring device comprising the above-mentioned displacement sensor 6.7, position sensor 8, and calculator 9, and 11 is an indicator for signal 9a. The first and second displacement sensors 6.7 are arranged so that the angle at which their tips look into the axis of the runner shaft 1a is 90 degrees.

FIG. 2 is a view of the main part in FIG.
The first displacement sensor 6 is disposed so that its tip faces the tip 2a of the runner vane, and its tip end surface is aligned with the inner surface of the water turbine casing 4. Although the second displacement sensor 7 of FIG. 1 is not shown in this figure, this sensor 7 is also attached to the water turbine casing 4 in the same manner as the sensor 6.

In FIGS. 1 and 2, a runner clearance monitoring device 10 is shown.
is configured as described above, when the runner 1 is nearly stationary, the output signals 5a, 7a of the displacement sensors 6.7
The results are almost as shown in Figure 3, but runner 1
When the rotational speed increases, both output signals (5a, 7a are the fourth
The result will be as shown in the figure. Fig. 4 11A), (13)
, (Q is a water turbine load of 6 M'W, 18
Signal 6 observed when MW was equivalent to 32.5 MW
In the waveform diagram of a, in FIGS. 3 and 4, t indicates the elapsed time, H indicates the displacement of the tip 2a of the runner vane from the reference position, and the numbers in ) indicate the vane number. The reference position of the vane tip 2a is a position appropriately set near the vane tip 2a when the runner 1 is stationary. In line with the direction in which the gap size δ shown in the figure i6 decreases (
・Ru.

The reason why the signal waveform has a comb-like shape in FIGS. 3 and 4 is because the vane tip 2a approaches or moves away from the displacement sensor as the runner 1 rotates, and the comb-like shape occurs as the turbine load increases. This is because the vane 2 is tilted in the direction of the runner axis 1a as the turbine load increases, and the relative time that the vane tip 2a faces the displacement sensor 6 becomes shorter, and The reason why the tips of the comb teeth have a triangular shape is that the vane tips 2a are deformed by the centrifugal force caused by the rotation of the runner 1 and the external force caused by the water flow.

Output signal 6a of displacement sensor 6.7 in FIG.

7a is 5 as described above, but in FIG. is constructed as shown in FIG. That is, in FIG. 5, 13, 14 and 15 are signals 6a and 15, respectively.
7a, 3a are input and output signal 13 according to each input signal
The amplifier circuit 16 outputs signals a, 14a, and 15a, and the runner 1 in FIG.
Delay circuits 17 and 18 output the Norse signal 16a after the time T required to rotate the vane by the angle of 1.degree., and the signals 13a and 14a are manually inputted to each of the five vanes 2 shown in FIG. The minimum value Hm% of the displacement I-1 shown in Fig. 4 is detected at ℃, and the signal 17a*18 corresponding to this minimum value is detected.
This is a peak value detection circuit configured to output a'Y, respectively. 2 in FIG. 1, the displacement sensor 6.7 is arranged in the water turbine casing 4 as described above, so that the signal 17
The Hm phase signal corresponding to, for example, one vane 2 among the five vanes 2 is when the runner 1 is the first one.
If it rotates in the direction of the arrow in the figure, it will appear in the signal 18a after the rotation time T has elapsed. 1
9 inputs the signal 15a and the signal 17a, and for each revolution of the runner 1 shown in FIG. An absolute value comparison circuit 20 selects lHminl and outputs a signal 19ag according to the selection result, and a signal 16a and a signal 18a are manually inputted to the absolute value comparison circuit 20 for each rotation of the runner 1 shown in FIG. Absolute value comparison circuit that compares the absolute displacement Hmin (i l Hmin l for the five vanes 2 and selects the maximum IHminI7z) and outputs a signal 202 according to this selection result, 21 is a comparison circuit for comparing both absolute values. This is a maximum value selection circuit which receives the output signals 19a + 20a of the circuits 19 and 20 and outputs a signal 9a corresponding to the larger value of both signals when the signal 16a is manually input. , is comprised of the above-mentioned amplifier circuits 13 to 15, delay circuit 16, peak value detection circuit 17, 18, absolute value comparison circuit 19, 20, and maximum value selection circuit 21. Arithmetic unit 9 is constructed as described above. Therefore, the output signal 9a is output from the displacement sensor 6.7.
The maximum value ηζ of the absolute displacement amount of the runner vane tip 2a from the above-mentioned reference position observed by In the part of the vane tip 2a located symmetrically with respect to the axis of the runner shaft 1a in the figure, the displacement H is considered to have a negative sign, so the signal 9a can be used to continuously adjust the gap δ shown in FIG. It will be possible to monitor.

In FIG. 1, the runner gap monitoring device 10 is configured as described above, so that the gap size δ can be directly and continuously detected by the output signal 9a of the arithmetic circuit 9. The present invention is not limited to the embodiment (the number of displacement sensors may be further increased, for example, to the same number as 20 vanes, and the displacement sensors may be arranged so that the spacing between adjacent sensors is the same). Furthermore, the computing unit 9 is connected to the runner vane tip 2.
The configuration may be such that it outputs a signal corresponding to the maximum displacement of the position sensor a and also outputs a signal indicating the number of the runner vane 2 indicating the maximum displacement using the output signal 8a of the position sensor.

〔Effect of the invention〕

As described above, in the present invention, a plurality of displacement sensors for detecting the distance to the runner vane, which are fixed to the water turbine casing so as to face the tip of the runner vane in a water turbine having a movable runner vane, and the displacement sensors of these sensors are provided. A water turbine launching gap monitoring device is composed of a calculator that receives each output signal of the sensor and performs predetermined calculations and outputs a signal Y corresponding to the maximum displacement of the runner vane tip. Since the size t of the gap between the water turbine and the casing is detected, the water turbine runner gap monitoring device has the effect of directly and continuously detecting the size of the gap.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention, and FIG.
Fig. 3 is an explanatory diagram of the output signal of the displacement sensor in Fig. 1, Fig. 4 (person), Fig. 4 (B), Fig. 4 (
C) is a diagram of different output signal waveforms of the displacement sensor in FIG. 1, and FIG. 5' is a block diagram of the arithmetic unit in FIG. 1. 2...Runner vane, 2a...Tip of runner vane, 4...Casing, 6...
...First displacement sensor, 7...2g2 displacement sensor, 9...computer, 10°°゛゛ water turbine runner gap monitoring device, δ...gap size . Figure 2 fA 3 Figure (A) (8) (C) Figure 4

Claims (1)

[Claims] A plurality of displacement sensors for detecting the distance to the runner vane are fixed to the casing of the water turbine so as to face the tip of the runner vane in a water turbine having a movable runner vane, and each output signal of the displacement sensor is inputted to a predetermined value. and an arithmetic unit that performs the calculation and outputs a signal according to the maximum displacement of the tip of the runner vane, and detects the size of the gap between the tip of the runner vane and the casing based on the output signal of the arithmetic unit. A water turbine runner gap monitoring device characterized by: