JPH0310036B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to monitoring failures related to runner bodies in hydroelectric power plants and preventing serious accidents.

[Background of the invention]

Power plants, especially hydroelectric power plants, have recently become largely unmanned due to the geographical conditions of their construction sites and the centralization of operation control, and each water system is generally controlled remotely and centrally from a parent control center. Ta. However, in order to maintain stable operation of hydroelectric power plants, maintenance personnel must conduct periodic inspection inspections, as has been done in the past. This maintenance and inspection is carried out at power stations scattered deep in the mountains, which requires a great deal of effort, especially in the winter. In order to save labor, there is an extremely strong desire to automate daily patrol inspection work, add equipment abnormality diagnosis functions to this, and detect and prevent accidents before they occur. For example, JP-A-56-113060 and JP-A No. 57-102573 protect against pump abnormalities, but they do not take measures from the perspective of prevention.

Furthermore, pumped storage power plants are used to generate peak load power in contrast to the base load power generation of nuclear and large thermal power plants due to their excellent load responsiveness. It contributes to the economic operation of the entire combined power system, and the need for this is expected to increase in the future. Therefore, in order to meet the demands from these systems, the frequency of starting and stopping of the main engine is increasing, and the operation modes are becoming more diverse due to the addition of phase adjustment functions. On the other hand, main engines tend to have higher speeds and larger capacities due to economic considerations, and once an accidental failure occurs, it is inevitable that it will take a huge amount of time and cost to repair. Installation of equipment is desired. Among the failures that can be expected regarding the main engine, one of the ones that will have the greatest impact is damage to the runner body. This is because, as mentioned above, most pumped storage power plants have extremely high heads in order to increase capacity, and although research has been done on the strength of the runners, in reality there are cracks in the runner blades, etc. , damage and other problems may occur.
This phenomenon is difficult to detect at an early stage, and can be easily detected when a damaged runner blade destroys the casing and produces abnormal noise. At this point, the entire main engine, including the runner and casing, will have to be repaired, which will take a huge amount of time and money. Therefore, it is important to discover cracks in the runner body at the initial stage and before a serious accident occurs. The desire to prevent this has become even stronger.

[Purpose of the invention]

The object of the present invention is to eliminate the drawbacks of the prior art and to detect runner damage at an early stage, which is a serious accident for hydropower plants.

[Summary of the invention]

The present invention uses a computer to realize a device that automatically detects runner failure at an early stage by distinguishing the vibration values of the water wheel shaft, water pressure pulsation, and runner top cover due to runner imbalance caused by cracks in the initial stage from vibrations caused by other malfunction phenomena. This makes it possible to prevent serious accidents.

[Embodiments of the invention]

An example of the present invention is shown below.

If cracks appear or show signs of cracking in the runner blades, the balance with respect to runner rotation will be lost, and
Abnormal vibrations that are different from normal occur in the main shaft, water pressure pulsation, and upper cover, and if operation continues without being able to detect this abnormal vibration, the casing, runner liner, etc. will be damaged.

Therefore, for early detection, it is first necessary to constantly monitor the vibrations of the main shaft and upper cover.

Main shaft vibration detection will be explained using FIG. 1. Figure 1 shows the mounting position of the spindle vibration sensor. The sensor is attached to the coupling part 12 of the generator shaft 13 and the water wheel shaft 14. In order to attach the sensor to the coupling portion 12, a support fixing rod 15 is attached and sensors (displacement type or acceleration type sensor) 10, 11 are attached. It is sufficient to detect shaft vibration in two directions, X and Y in the figure, and a sensor 11 is installed in the X direction and a sensor 10 is installed in the Y direction.

The main shaft vibration is constantly detected in two orthogonal directions by the above sensor. Note that the normal vibration amplitude differs depending on the load during water turbine operation and depending on the head during pumping operation, so the set value is a function of the load and head, respectively.
FIG. 2 shows an example of the setting.

The actual measured value at a certain power plant is curve 2 in the direction of power generation.
The function form is curve 22 on the 0 pumping side. Although this value differs depending on each power plant, it shows almost the same tendency.
Figure 2 shows the vibration amplitude values under normal conditions.
From this, if the values measured by sensors 10 and 11 are larger overall than the judgment values 21 and 23,
The amplitude value is determined to be abnormal, and the runner fault detection device detects various abnormal causes to determine whether the abnormal spindle vibration is due to a runner fault. Other factors contributing to this include upper cover vibration and water pressure pulsation, which will be discussed later. Incidentally, although the vibrations are monitored here in terms of overall values, it is often the case that only vibrations at a certain frequency are large.
In other words, only frequencies that are an integral multiple of the value determined by the number of runner blades, rotation speed, etc. cause large vibrations, so it may be difficult to detect abnormalities early based on overall values. Therefore, this sensor 1
The values of 0 and 11 are subjected to frequency analysis, and the results are monitored as a function of absolute displacement and frequency to detect abnormalities. Figure 3 shows the relationship. The actual measurement value 31 has a large amplitude at a frequency when the number of runner blades N=5, and also shows a relatively large amplitude at frequencies of 2×N (=5)×Zr (=6) and 3×N×Zr. If a failure occurs in the runner, a large amplitude value will be shown at a different frequency, indicating that an abnormal factor has affected the runner. For this reason, a curve such as a set value 30 is stored in the computer, and the values measured by the sensors 10 and 11 are frequency-analyzed, and this and 30 are compared to detect an abnormality. Once spindle vibration abnormality has been detected using the two methods above, the method for detecting runner failure will be described below. The fourth system to do that
As shown in the figure.

FIG. 4 shows an example of the configuration of the monitoring system of the present invention.
This system is plant equipment (hydroelectric power generation equipment) 54
Perform data entry. First, the vibration value 55 of the main shaft is converted to a computer input level by the converter 51, and the vibration data input section 4 inside the computer main body 41
7 into the computer. The main shaft vibration value 55 can be determined by measuring the amplitude of the vibration, by monitoring the sound, or by measuring the frequency component of the vibration, but the method is determined according to the characteristics of the main engine of each power plant. The computer main body 41 includes a CPU 42 that performs arithmetic processing, a system program memory 43 that stores programs such as algorithms, a data memory 44 that stores data, and a data output typewriter 45 that prints and displays automatic judgment results, etc. A vibration data input section 47 for inputting vibration values, an analog measurement value input section 48 for inputting measured values of data used to determine the cause of vibration, and a digital data input section 49 for inputting program starting conditions such as starting and stopping the main engine. , a digital data output section 50 for outputting alarm data 70 to an alarm display 53 when an abnormal value is found, and a computer internal interface bus 46 for exchanging these data with the CPU 42. Further, the analog measured value must be converted to a computer input level, and this is done by analog data converter 52.

The measured values used to determine the cause of vibration are upper cover vibration value 56, bearing gap value 57, bearing lubricating oil level value 58, bearing cooling water flow rate 59, bearing cooling water temperature 60, head difference 61, load 62, and water pressure pulsation. value 63, guide vane servo motor differential pressure 64, weak point pin breakage data 65, air supply flow rate 66, upper cover bolt loosening conversion 67, and runner seal gap temperature 68.

FIG. 5 shows the computer processing flow of the monitoring system. The computer program is always activated periodically by a timer (not shown). When the program is started, first, each input data (55 to 69) is input (A) and stored in the data memory 44 in FIG. 4 (B). At this point, only data input and data storage into memory are performed. Next, the main shaft vibration value 55 is retrieved from the memory, and it is determined whether the vibration value 55 deviates from the allowable value according to the algorithms shown in FIGS. 2 and 3 (C). If this value 55 is within the allowable value, it is determined that there is no abnormality in the operation of the main engine, and the program processing is terminated. On the other hand, if the vibration value 55 deviates from the allowable value in the determination (C), processes D to F are performed as an abnormality determination routine. First, an alarm is output to notify that there is an abnormality in the operation of the main engine.
(D). The alarm data 70 is displayed on the alarm display 53 via the digital output section 50. Next, the computer analyzes the cause using the previously stored analog measurement values (56 to 68) in order to discover which malfunction in the main engine is the cause of the abnormal vibration value (E). Since the cause of the vibration is clarified by this process E, it is typed out and displayed on the data output typewriter 45 (F). As a result, even if the vibration value becomes abnormal, it no longer takes time or is impossible to find the cause, and the time for inspection and investigation becomes much shorter. Furthermore, if the power plant is unmanned, the alarm display 53 and data output typewriter 45 may be installed at a remote control center.

During the processing shown in FIG. 5, abnormality processing routines D to F place a much greater burden on the CPU (calculation processing time becomes longer) than routines A to C. This situation can be seen in the 6th
Illustrated with diagrams. FIG. 6 is a diagram showing temporal changes in the arithmetic processing of the CPU 42, divided into when the vibration value is normal and when the vibration value is abnormal. In FIG. 6, the horizontal axis indicates the elapsed time t, and T indicates the time period in which the program is started by a hard timer (not shown). First, during normal operation, the processing of each input data input A, input data storage B, and vibration value determination C shown in FIG. 6 is performed (section), and then the computer shifts to idle time. In other words, if the vibration value is within the allowable value, the CPU is mostly in the idle section,
Doesn't require a very fast CPU. Next, when the vibration value is abnormal, it is necessary to perform a section in which the alarm output D, vibration cause determination routine E, and data type out F are performed after the section in which the same processing as described above is performed. This interval requires complex processing that places a large load on the CPU, so it takes a long time to process. However, this process does not work normally. In normal conditions, the conventional method performs this at each calculation processing interval, but with this method, there is no need to perform this, so the load on the CPU is much lighter. If the process takes a long time,
Even if the period T is extended only in the event of an abnormality, the responsiveness of the entire system will not be affected much.

FIG. 7 shows an algorithm for the vibration cause determination routine E shown in FIG. When the spindle vibration abnormality 101 is indicated, this algorithm is activated. Main shaft vibration abnormalities are caused by all of the factors enclosed in the squares in FIG. 7. Broadly speaking, there are two types of abnormalities: those caused by upper cover vibration and those that are not. Therefore, a determination 102 is made as to whether the upper cover vibration value also shows an abnormal value. 201-2 if there is no upper cover vibration value abnormality
Since the cause of 04 is considered, the determination processing of 103 to 105 is performed. First, there is an abnormality in the fixed part of the bearing gap 2.
To determine whether 01 has occurred, the gap value is measured using a gap sensor attached to the bearing gap, and it is determined whether the gap value exceeds a specified allowable value (103). Furthermore, when there is a lack of bearing lubricating oil, vibrations occur due to lack of lubrication 202, so the bearing lubricating oil level is measured by a level sensor, and it is determined 104 whether or not it deviates from the allowable value. . Furthermore, since damage to bearings due to cooling water cutoff 203 can be a major cause, the bearing cooling water flow rate is measured with a flow meter, and it is determined whether or not the cooling water flow rate exceeds an allowable value.
Furthermore, the temperature of the cooling water is measured using a resistance temperature detector or the like, and an abnormal temperature rise is determined (105). If the main shaft vibration is abnormal and the top cover vibration is normal in other cases, the generator electromagnetic excitation force is abnormal or the water turbine balance is abnormal (20
4) is possible, so type out the necessity of detailed inspection. On the other hand, if the upper cover vibration value is also abnormal, the causes 205 to 212 are possible, so determinations 106 to 113 are performed. First, if it is an effect due to head 106 or an effect due to load 104, it can be determined that there is a problem with the characteristics of the water turbine itself, so long-term monitoring measures (205) or detailed investigation are required. Inspect and notify maintenance personnel. If 106 and 107 are normal, the draft water pressure, runner back pressure, etc. are measured using a pressure displacement sensor, and it is determined whether the water pressure pulsation value is within an allowable value (108).
If the water pressure pulsation value is normal, possible causes are 206-209, and if it is abnormal, 210-21
There are two causes. First, if it is normal, an air supply abnormality 206 during pumping is considered, and this is measured using an air supply flow meter to determine whether the air supply flow rate is abnormal 109. If 109 is normal, there is a cause of loosening of the upper cover seam bolt 207, and the displacement of this bolt loosening is measured with a gap sensor and determined (1
10). If 110 is normal, there is a cause of runner seal damage 208, and this is determined by the runner seal gap temperature sensor as a temperature abnormality (1
11). Others are the cause of damage 209 to the upper cover itself. On the other hand, if the water pressure pulsation value 108 is determined to be an abnormal value, factors 210 to 212 are considered, and in the case of guide vane damage 210,
In order to monitor the cause of guide vane metal galling, etc., the operating force of the guide vane servo motor is measured (differential pressure is measured) (112) and a determination is made. If it is not the cause of 210, the weak point pin breakage 211 is considered, and this determination is made by the breakage detection sensor (11
3). Other than this is the cause of the target runner failure (due to damage, etc.) 211 and requires detailed inspection, so it is typed out and displayed as requiring preventive maintenance.

To find this runner damage: (1) Main shaft vibration value (2) Upper cover vibration value (3) Head (4) Load (5) Water pressure pulsation value (6) Guide vane servo motor differential pressure (7) Broken weak point pin Of the above, (1) has already been explained. Furthermore, (3), (4), (6), and (7) can be easily measured using conventional techniques. For this reason, the measurement and determination methods for (2) and (5) are shown below.

Figure 8 shows the measurement points for upper cover vibration and water pressure pulsation. Upper cover vibration is constantly detected in two directions: horizontal and vertical. The horizontal sensor mounting position is 300, and the vertical sensor mounting position 301 are both located on the upper cover. In addition, in Figure 8, runner 30
5. Main shaft 306 and casing 304 are shown. Further, the water pressure pulsation constantly detects the runner back pressure, and the vibration sensor is installed at position 302.

Figure 9 is a diagram showing the upper cover vibration. The upper cover vibration shows a unique tendency for each individual hydropower station, but judging from the actual measurements 311 and 312, when the turbine is in operation, it is a function of the load and head. 310, during pumping operation, it can be expressed as a function 313 of pumping head. However, on the water turbine operation side, the influence of head is often small, and in that case it becomes a function of load.

In actual measurement, the vibration amplitude value is monitored as an overall value. A value in which the measured value exceeds the setting functions 310 and 313 is determined to be abnormal.

Figure 10 is a diagram showing water pressure pulsation (runner back pressure). Although water pressure pulsation also shows a unique tendency for each individual hydroelectric power plant, judging from the actual measured values 321 and 323, when operating a water turbine, the load It can be expressed by a function 320 and a function 322 of pumping head during pumping operation.

In the actual measurement, the vibration amplitude value is monitored as an overall value, and if the actual measurement data exceeds the setting functions 320 and 322, it is determined that there is an abnormality.

Regarding water pressure pulsation, the water flow section design method, pipeline, turbine push-in depth, type of water turbine (dedicated machine, pump turbine,
Francis turbine, diagonal flow turbine, etc.) and cannot be expressed using a common formula for hydroelectric power plants.
It is often determined by testing.

In this way, in order to discover runner failures early, in this example, the spindle vibration caused by the runner imbalance that appears in the early stages is constantly monitored from both the overall value and the frequency analysis value, and when an abnormality is detected, , other failure factors that cause spindle vibration are automatically detected, processed by a computer, and automatically determined, making it possible to immediately detect runner failures. In the present invention, the computer is in idle operation during normal operation, but it is also possible to organize the maximum and minimum of measurement data in this section and perform operations such as daily reports, monthly reports, etc., and the computer can be used effectively. Furthermore, although the present invention applies the fact that malfunctions in the main hydropower generator are mainly caused by vibrations of the main shaft of the water turbine, the algorithm shown in Fig. 7 can be modified and the sensor installed for thermal power generation equipment with similar characteristics. It can be applied by considering the location. In this case, the system configuration will be the same hardware (computer system) configuration as the present invention.

〔Effect of the invention〕

According to the present invention, vibrations can be automatically monitored and serious accidents can be prevented and detected early using a microcomputer.Furthermore, in the event of an abnormality, the cause can be shown, thereby greatly shortening the investigation time and allowing appropriate processing to be carried out. .

[Brief explanation of the drawing]

Figure 1 is the installation diagram of the spindle vibration sensor, Figure 2 is the spindle vibration algorithm, Figure 3 is the spindle vibration frequency analysis algorithm, Figure 4 is the configuration diagram of the monitoring computer system, Figure 5 is the computer processing flow diagram, and Figure 6 is is the computer processing time time chart, Figure 7 is the algorithm for determining the cause of vibration value abnormality, Figure 8 is the water pressure pulsation,
Fig. 9 shows the upper cover vibration sensor installation diagram, Fig. 9 shows the upper cover vibration algorithm, and Fig. 10 shows the water pressure pulsation (runner back pressure) algorithm. 41... Computer body, 42... CPU, 43...
...System program memory, 44...Data memory, 45...Data output typewriter, 46...Computer internal interface bus,
47... Vibration data input section, 48... Analog measurement value input section, 49... Digital data input section,
50... Digital data output section, 51... Vibration data converter, 52... Analog data converter,
53...Alarm indicator, 54...Plant equipment, 5
5... Main shaft vibration value, 56... Upper cover vibration value, 5
7... Bearing gap value, 58... Bearing lubricating oil level value, 59... Bearing cooling water flow rate, 60... Bearing cooling water temperature, 61... Head, 62... Load, 63...
Water pressure pulsation value, 64... Guide vane servo motor differential pressure, 65... Weak point pin breakage data, 66... Air supply flow rate, 67... Upper cover bolt loosening displacement, 6
8...Runner seal gap temperature, 69...Main engine starting status, 70...Alarm data.

Claims (1)

[Claims] 1. In a water turbine runner failure detection device that detects a shift in the rotational balance of a water turbine runner, a means for detecting and capturing vibrations of the water turbine runner is compared and determined by comparing the captured vibration with predetermined vibration data due to cracks and damage of the runner blades. means for outputting an alarm if the captured vibration is determined to be the predetermined vibration, means for searching for the cause of the vibration, and means for outputting the cause of the vibration. A water turbine runner fault detection device featuring: