JPS61215459A - Shaft shift monitoring device for hydraulic machine - Google Patents

Abstract

PURPOSE:To enable early detection of shifting of shaft system by providing sensor group for detecting the pulsating hydraulic pressure at each portion, sensor group for detecting the temperature distribution of guide bearing in circumferential direction, sensor group for detecting the thickness of oil film at the guide bearing and sensor group for detecting the shift at each portion in the shaft system. CONSTITUTION:Sensors (a)-(e) are provided to detect the pulsating hydraulic pressures in the casing 1, the back pressure chamber 14 at the outside of runner, the back pressure 13 at the inside, the side pressure chamber 17 and the upper suction tube 8. Furthermore, a plurality of sensors (f) for detecting the temperature distribution of a guide bearing 10a in circumferential direction, sensors (g) for detecting the thickness of oil film formed between the guide bearing 10a and the spindle 7 and sensor (h) for detecting the shift of spindle 7 are provided. It is decided that the shaft has shifted if the outputs from the sensors (f)-(h) have exceeded over respective limits even though the pulsating hydraulic pressures to be detected through the sensors (a)-(e) are within respective limit thus to produce a shaft shift signal.

Description

Detailed Description of the Invention (Techniques of the Invention, Both Fields) The present invention provides a system in which a hydraulic machine and a rotary electric machine are arranged on one axis, and a plurality of them are arranged on the axis system of a hydraulic machine device in which a hydraulic machine and a rotary electric machine are arranged on one axis and are also connected to each other on the stationary side. The present invention relates to an axial misalignment monitoring device for monitoring axial misalignment of a guide bearing.

[Technical background of the invention and its problems]

Although the proportion of hydroelectric power generation in total power generation has been gradually decreasing in recent years, unlike thermal power generation or nuclear power generation, it has the advantage of being able to secure power in a short time and adjust output over a wide area. Its importance has not diminished even today. On the contrary, due to such importance, accidents and failures of hydroelectric power generation equipment can even be said to include the possibility of causing major social problems. Therefore, such hydroelectric power generation equipment is required to have high reliability. One of the requirements for this high reliability is the problem of keeping the misalignment, or eccentricity, between the respective guide bearings that support the shaft system from the generator to the water turbine within a predetermined value. This eccentricity between the guide bearings is difficult to detect, and if it exceeds a predetermined value, it may lead to a major accident such as abnormal vibration of the shaft system or damage to the bearings. Such axis misalignment occurs due to crustal deformation over time in underground or semi-underground power plants, and there is no way to prevent this, and since the changing layer is small, it is difficult to directly measure axis misalignment in a short period of time. is extremely difficult to detect, and is often undetectable until the amount of axis misalignment becomes considerably large after a long period of time. In some cases, there was a risk that an abnormality would only be discovered after a bearing damage accident occurred.

When such a bearing accident occurs, it generally takes a long time to recover, and the amount of power lost due to the stoppage of the main engine during that time is enormous. Therefore, instead of directly detecting the secular misalignment abnormality of the shaft system from the amount of misalignment, a method of indirectly detecting it based on measured values such as temperature distribution and oil film thickness of each bearing may be considered. However, with this method, it is not possible to determine whether an abnormality occurring in the bearing is due to a misalignment of the shaft center, an increase in the external load, or an abnormality in the sensor itself.

This situation occurs not only in power generation equipment consisting of a water turbine and a generator, but also in pump equipment consisting of a pump and an electric motor that drives it, or when the same equipment is used for power generation and pump operation, such as in pumped storage power plants. This can also happen when used reversibly.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and
The purpose is to provide a shaft misalignment monitoring device that can detect misalignment of the shaft system caused by building movement over time during constant monitoring, and can prevent major accidents such as bearing accidents.

[Summary of the invention]

In order to achieve the above object, the present invention provides a casing of a hydraulic machine in a hydraulic machine in which a hydraulic machine and a rotating electric machine are arranged on one axis and are also connected to each other on the fixed side;
Runner outer back pressure chamber, runner inner back pressure chamber, lance side pressure chamber,
and a first sensor group that polarizes each water pressure pulsation in the upper suction pipe, and a plurality of second sensors arranged on each bearing to detect the circumferential temperature distribution of each guide bearing arranged on the shaft system. a third sensor group that detects the oil film thickness of each guide bearing; and a fourth sensor group that detects the runout of each part of the shaft system.
a group of sensors, a group of comparators that output an output signal when each detection target obtained based on the output signal of each of the sensor groups exceeds a preset limit value, and a group of comparators that output an output signal based on the output signal of the group of comparators. Although each water pressure pulsation detected by the first sensor group does not exceed each limit value, the second
゜3rd. It is characterized by comprising an alarm circuit that determines that axis misalignment has occurred when each detection target detected by each of the fourth sensor groups exceeds each limit value, and outputs an axis misalignment signal. That is.

(Embodiment of the Invention) Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

First, the mounting positions of each sensor will be explained with reference to FIG. Fig. 3 shows the main parts of a hydraulic machine such as a water wheel or a pump water wheel. If the water wheel is operated now, pressurized water is introduced into the casing 1 from an iron pipe (not shown) into the stay ring 2. After being adjusted by the guide vane 5, the flow flows into the runner 6 disposed within the pressure chamber formed by the upper cover 3 and the lower cover 4, releases potential energy as torque energy, and then flows into the upper suction pipe 8. It passes through a draft tube (not shown) and reaches a lower pond (not shown).

The torque obtained by the runner 6 is transmitted to a generator (not shown) via the main shaft 7 and converted into electrical energy.

When the pump is in operation, the flow of energy is completely reversed, and water from the lower pond is pumped into the upper pond by the pump driven by the electric motor.

A main shaft water sealing device 9 is provided at the main shaft penetrating portion of the upper cover 3 in order to prevent water in the pressure chamber from flowing out to the outside.
A guide bearing device 10 that rotatably supports the main shaft 7 is provided.

In the case of a high head machine, a back pressure chamber formed by the runner crown 11 and the upper cover 3 is divided by an intermediate seal 12 into an inner back pressure chamber 13 and an outer back pressure chamber 14. In that case, the intermediate seal 12 is arranged on the same radius as the outlet seal 16 on the runner band 15 side, thereby making the pressures in the outer back pressure chamber 14 and the side pressure chamber 17 almost the same and preventing the generation of excessive thrust force. Do it like this.

In the hydraulic machine having the above configuration, a sensor a is provided to detect water pressure pulsations in the casing 1, and similarly, the sensor a is installed in the outer back pressure chamber 14, the inner back pressure chamber 13, the side pressure chamber 17, and the upper suction pipe 8. Sensors b, c, d and e are provided to detect each water pressure pulsation. A sensor f is provided to detect the temperature of the guide bearing 10a included in the guide bearing device 10, and a sensor Q is provided to detect the thickness of the oil film formed between the guide bearing 10a and the main shaft 7. Furthermore, a sensor h is attached to the upper part of the guide bearing assembly *io to detect the shaft runout of the main shaft 7.

Although only one sensor a to h is shown, a plurality of sensors a to h may be provided if necessary. In particular, a plurality of temperature detection sensors f are provided along the circumferential direction in order to detect the temperature distribution in the circumferential direction of the bearing.

FIG. 1 shows an embodiment of the axis misalignment monitoring device of the present invention, which includes sensors a to h of FIG. 3. The detection signals 21 to 28 of each sensor a to h are sent to the comparator 3.
1 to 38 and recorded by the recorder 64.

Comparators 31 to 38 compare the magnitudes of detection signals 21 to 28 with respective allowable limit values input to reference input terminals (not shown), and when the former exceeds the latter, an abnormality signal 4 is generated.
Outputs 1 to 48. These abnormality signals 41 to 48 are input to the alarm circuit 50 as well as to the display 63 and recorder 64. The alarm circuit 50 sends abnormal signals 41 to 48
of off-axis based on.

The presence or absence is determined, and when it is determined that there is an axial misalignment, an axial misalignment signal 61 is output to an audible alarm 62 to issue an audible alarm. The axis deviation signal 61 is also input to a display 63. The display 63 visually displays the individual abnormality signals 41 to 48 and the axis deviation signal 61 based on each input signal together with the abnormality location as necessary. The recorder 64 records the detection signals 21-28 of each sensor, and also records the abnormal signals 41-48 from each comparator 31-38.

The recording results of the recorder 64 can be used to investigate the cause of axis misalignment, or can be used to investigate changes over time in various recording objects even when axis misalignment has not occurred.

FIG. 2 shows an example of the configuration of the alarm circuit 50. The alarm circuit 50 essentially consists of an AND circuit 51.

The AND circuit 51 receives inverted abnormality signals 41 to 45 of water pressure pulsations detected by the sensors a to e, and also inputs the bearing temperature, oil film thickness, and oil film thickness detected by the sensors f to h.
and an abnormal signal 46 to indicate that the shaft runout is abnormal.
48 is input as is, and the AND of these input signals (
(AND) condition, the axis misalignment signal 61 is output.

Since each part of the hydraulic machine shown in FIG. 3 has a finite number of runner blades and guide vanes 5, mutual interference inevitably causes water pressure pulsations specific to each part to be thermally large or small. The absolute value of these water pressure pulsations does not change significantly unless an abnormality occurs in the flow path. therefore,
If the magnitude of the water pressure pulsations detected by the sensors a to e placed at each part of the flow path from the casing 1 to the upper suction pipe 8 are all smaller than a preset value, there is no particular abnormality in the flow path. It can be determined that there is no such thing. Regarding the above, in the apparatus of FIG. 1, the detection signals 2 of sensors a to e are
1 to 25 are compared with the allowable limit values by the comparators 31 to 35, and if the water pressure pulsations represented by the detection signals 21 to 25 are within the allowable limit values, the comparators 31 to 35 output a "0" signal.
Also, if the allowable limit value is exceeded, a "1" signal is output. On the other hand, the difference in the concentration of each part of the bearing detected by the temperature detection sensor f provided at multiple locations in the circumferential direction of the guide bearing 10a, or the amplitude value of the bearing oil film thickness detected by the sensor Q, The absolute value of the shaft runout detected by the sensor h provided near the shaft 10a is compared with the respective allowable limit value by the comparators 36 to 38, respectively. If the result of this comparison is within the allowable limit value, comparator 3
6 to 38 output an "O" signal, and when the allowable eye field value is exceeded, a "1" signal is output. Here, the comparators 36 to 38 are “
Outputting a 1'' signal means that the load component in a specific direction on the shaft system is increasing due to some external cause.

Note that each allowable limit value set in the comparators 31 to 38 can be changed depending on the operation mode, that is, generation mode, pumping mode, phase adjustment, partial load, AFC (automatic frequency adjustment), etc. Let's do it like this.

With the above circuit configuration, the alarm circuit 50 outputs abnormal signals 41 to 41.
45 are each "0", and when the abnormality signals 46 to 48 are each "1", the axis misalignment signal 61 is output. In other words, the water pressure pulsation in each part is normal (
-“0”), the bearing temperature difference, oil film thickness, flea width, and shaft runout absolute value are abnormal (-“1”).
), it is determined that an axis misalignment has occurred.

If an abnormal signal similar to the axis misalignment signal 61 is generated, the indicator 63 will be displayed.
Signs of abnormality can be detected in advance from the displayed contents and the recorded contents of the recorder 64.

The circuit portions shown in FIGS. 1 and 2 can also be implemented by computer software. Furthermore, depending on the structure of the hydraulic machine, the locations and number of sensors for detecting water pressure pulsations may be arranged in locations other than those shown in the figures.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to detect misalignment of the shaft system caused by building movement over time, which has been extremely difficult to detect in the past, without stopping the main engine through constant monitoring.
Moreover, it becomes possible to detect abnormalities from the early stages.
Further, it is possible to provide a highly reliable axis misalignment monitoring device that allows easy investigation of the location and cause of abnormality.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a block diagram showing details of the alarm circuit in the device shown in Fig. 1, and Fig. 3 is a hydraulic machine showing the sensor mounting device in Fig. 1. FIG. 1...Casing, 6...Runner, 7...Main shaft,
8... Upper suction pipe, 10a... Guide bearing, 13.
...Runner inner back pressure chamber, 14...Runner outer back pressure chamber,
17...Runner side pressure chamber, a-h...sensor, 31~
38...Comparator, 50...Alarm circuit, 62...Audio alarm, 63...Display device, 64...Recorder.

Claims (1)

[Scope of Claims] 1. A casing of a hydraulic machine, a back pressure chamber outside the runner, a back pressure chamber inside the runner, in a hydraulic machine device in which a hydraulic machine and a rotating electric machine are arranged on one axis and are also connected to each other on the fixed side. A first group of sensors detects water pressure pulsations in the runner side pressure chamber and the upper suction pipe, and a plurality of sensors are placed on each bearing to detect the circumferential temperature distribution of each guide bearing placed on the shaft system. a second sensor group, a third sensor group that detects the oil film thickness of each of the guide bearings, a fourth sensor group that detects the runout of each part of the shaft system, and an output signal of each of the sensor groups; a group of comparators that output an output signal when each detection target obtained based on the above exceeds a preset limit value;
Each water pressure pulsation detected by the first sensor group based on the output signal of this comparator group is detected by each of the second, third, and fourth sensor groups even though it does not exceed each limit value. An axis misalignment monitoring device for a hydraulic mechanical device, comprising an alarm circuit that determines that an axis misalignment has occurred when each detection target exceeds each limit value, and outputs an axis misalignment signal. 2. The axial misalignment monitoring device according to claim 1, further comprising an audible alarm that issues an audible alarm based on the axial misalignment signal from the alarm circuit. 3. The axis misalignment monitoring device according to claim 1, further comprising a display that displays the outputs of the comparator group and the alarm circuit. 4. Claim 1, further comprising a recorder for recording the outputs of each of the sensor groups and the comparator group.
Axis misalignment monitoring device described in Section 1.