JP2018096315A - Liquid supply system for hydraulic power generation and method for supplying liquid to hydraulic turbine generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce abrasion of a main shaft of a hydraulic turbine generator caused by foreign matter.SOLUTION: A liquid supply system 100 for hydraulic power generation includes a filtering device 28 for filtering raw water and preparing filtered water from which at least a part of foreign matter contained in the raw water is removed, first piping L1 which connects a raw water source 4 with the filtering device 28 so as to supply the raw water taken from the raw water source 4 to the filtering device 28, and second piping L2 which connects the filtering device 28 with a hydraulic turbine generator 1 so as to supply the filtered water to the hydraulic turbine generator 1.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a liquid supply system for hydroelectric power generation and a method for supplying liquid to a water turbine generator, and more particularly to a liquid supply system for supplying water to a water turbine bearing or a water wheel shaft seal device of a water turbine generator.

  An oil lubrication method and a water lubrication method are known as bearing lubrication methods for the main shaft of a water turbine generator. The oil lubrication method has a risk of contaminating the surrounding environment due to oil leakage into the river. For this reason, in recent years, a water lubrication system that uses river water to lubricate bearings and can avoid the above-mentioned risks may be employed.

  In the water lubrication method, since river water is directly used as a bearing lubricant, it is necessary to prevent foreign matter from entering the sliding portion of the bearing. Patent Document 1 discloses a liquid supply system including a sedimentation facility and a centrifugal facility.

Japanese Patent No. 4628252

  In recent years, due to the effects of climate change, intensive heavy rains have been likely to occur in a short time. In addition, sudden volcanic eruptions can cause the ejecta to flow into rivers. For this reason, the property of the foreign matter in river water changes, and it is difficult to prevent the foreign matter from being mixed into the bearing using only the sedimentation separation equipment and the centrifugal separation equipment. Sedimentation separation equipment separates due to the difference in the sedimentation speed of foreign matter, while centrifugal separation equipment separates from the difference in angular momentum acting by rotation, but in both cases, the smaller the foreign matter particle size, the more difficult it is to separate water and foreign matter. This is because it has a fundamental problem. As a result, when the turbidity of the river is high, power generation must be interrupted or stopped to prevent wear, and when power generation is continued, wear of the main shaft of the turbine is likely to occur due to contamination of the bearings. Therefore, the frequency of large-scale repair and replacement work tends to increase. The shaft sealing portion of the bearing water tank that houses the bearing is also provided with a minute gap between the main shaft, and entry of foreign matter into the gap causes wear of the main shaft.

  In addition, during operation of the turbine generator, it is necessary to continuously supply cooling water to the main shaft and bearings. However, since the properties of foreign matter in river water fluctuate greatly as described above, cooling water having a certain treated water quality is required. There was a problem that stable and continuous supply was not possible.

  An object of the present invention is to provide a liquid supply system for hydroelectric power generation that can reduce the wear caused by foreign matters on the main shaft of a water turbine generator and can stably and continuously supply cooling water having a certain treated water quality. .

  The liquid supply system for hydroelectric power generation according to the present invention includes a filtration device that filters raw water to produce filtered water from which at least a part of foreign matter contained in the raw water has been removed, and connects the raw water source to the filtration device. A first pipe for supplying the raw water taken to the filtration apparatus; and a second pipe for connecting the filtration apparatus to the turbine generator and supplying filtrate to the turbine generator.

  According to the present invention, since at least a part of the foreign matter contained in the raw water is removed by the filtering device, it is possible to provide a hydroelectric power supply system that can reduce wear caused by foreign matter on the main shaft of the turbine generator. it can.

It is a schematic block diagram of the water turbine generator to which this invention is applied. It is a schematic block diagram of the liquid supply system for hydroelectric power generation concerning one embodiment of the present invention. It is an example of a measurement of the particle size distribution of the foreign material contained in the centrifuge outlet water. It is an example of observation with an optical microscope of water at the outlet of the centrifuge. It is an example of backwashing operation according to the differential pressure increase speed.

  Hereinafter, a liquid supply system for hydroelectric power generation according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 illustrates a schematic configuration of a water turbine generator to which the present invention is applied. FIG. 2 shows the concept of a hydroelectric power supply system (hereinafter referred to as system 100).

  Referring to FIG. 1, a water turbine generator 1 has a main shaft 2 to which a runner 3 is attached. The runner 3 is accommodated in a casing 5 connected to a hydraulic iron pipe 4 (see FIG. 2). A generator 7 is attached to the upper end portion of the main shaft 2 via a coupling 6. The river water supplied from the hydraulic iron pipe 4 rotates the runner 3 inside the casing 5, thereby generating power by the generator 7. The hydraulic iron pipe 4 is provided with an inlet valve 8 (see FIG. 2) for stopping the supply of river water during maintenance of the turbine generator 1.

  The main shaft 2 is supported by an underwater bearing (hereinafter referred to as a bearing 9). The bearing 9 is accommodated in a bearing water tank 10. The bearing 9 is a sliding bearing, and a minute gap 12 is provided between a collar 11 attached to the main shaft 2 and a sliding surface 9 a of the bearing 9. The bearing water tank 10 is filled with river water, and the river water flowing into the gap 12 lubricates the bearing 9 and cools the bearing 9 and the main shaft 2. A river water supply pipe (second pipe L2) and a river water discharge pipe L7 are connected to the bearing water tank 10, and the river water is continuously connected to the bearing water tank 10 from the supply pipe (second pipe L2). The river water whose temperature has risen is continuously discharged from the bearing water tank 10 to the river. A water wheel shaft seal device (hereinafter referred to as a shaft seal device 13) is provided in the penetrating portion of the main shaft 2 of the bearing water tank 10. The shaft seal device 13 prevents leakage of river water in the bearing water tank 10.

  Hereinafter, river water supplied from the hydraulic iron pipe 4 is referred to as “raw water”, and the hydraulic iron pipe 4 is referred to as “raw water source”. In this specification, for the sake of convenience, water flowing through a first pipe L1 described later is also referred to as “raw water”. That is, water treated by some treatment device such as the sedimentation separation device 22 and the strainer 23 installed on the first pipe L1 is also referred to as “raw water”. Similarly, in this specification, for convenience, water flowing through a second pipe L2 described later is referred to as “filtered water”. That is, water treated by some treatment device such as the desalination device 30 installed on the second pipe L2 is also referred to as “filtered water”. In other words, on the basis of the filtering device 28 which is a characteristic device in the present invention, water flowing upstream of the filtering device 28 is collectively referred to as “raw water”, and water flowing downstream of the filtering device 28 is referred to as “filtered water”. ". Raw water usually contains fine particles of minerals such as quartz and feldspar. A solid contained in the raw water, represented by these fine particles, is called “foreign matter”.

  The system 100 has a filtration device 28 for filtering raw water. At least a part of the foreign matter contained in the raw water is removed to produce filtered water, and the filtered water is supplied to the bearing water tank 10 in which the bearing 9 and the shaft seal device 13 of the turbine generator 1 are accommodated. The filtration device 28 is connected to the raw water source 4 by a first pipe L1 and is connected to the bearing water tank 10 by a second pipe L2. Therefore, the raw water taken from the raw water source 4 is supplied to the filtration device 28 through the first pipe L1 to become filtered water, and the filtered water is supplied to the bearing water tank 10 through the second pipe L2. A desalinator 30 is provided downstream of the filtration device 28. As the desalting apparatus, for example, a cartridge polisher filled with an ion exchange resin can be used. By removing the ionic component contained in the filtered water, it is possible to suppress the occurrence of rust on the main shaft 2.

  A sedimentation separator 22 is provided along the first pipe L1. The sedimentation separator 22 sediments and removes foreign matters having a relatively large particle size by gravity. A valve 21 is provided between the sedimentation separator 22 and the raw water source 4. By closing the valve 21, raw water is prevented from flowing into the sedimentation separator 22 during maintenance of the sedimentation separator 22.

  A strainer 23 is provided downstream of the sedimentation separator 22 in the first pipe L1, and foreign substances having a relatively large particle size that have not been separated by the sedimentation separator 22 are removed. A centrifugal separator 25 is provided downstream of the strainer 23 of the first pipe L1. The centrifugal separator 25 separates, from the raw water, a foreign matter having a specific gravity greater than 1 that cannot be removed by the strainer 23 and has a specific gravity of water. The separated foreign matter is discharged to the river through the pipe. A valve 24 is provided on the inlet side of the centrifugal separator 25. By closing the valve 24, raw water is prevented from flowing into the centrifugal separator 25 during maintenance of the centrifugal separator 25.

  A bypass pipe L3 branches from the first pipe L1 downstream of the centrifugal separator 25 of the first pipe L1. The bypass pipe L3 bypasses the filtration device 28 and is connected to a filtered water tank 36 described later. The end of the first pipe L1 on the downstream side of the centrifugal separator 25 is connected to the filtration device 28.

  A filtration water tank 36 is provided via a valve 31 on the downstream side of the filtration device 28 of the second pipe L2. The filtered water tank 36 stores the filtered water filtered by the filtering device 28. As a result, even when the supply amount of the raw water fluctuates, or when the equipment on the upstream side of the filtration water tank 36 (sedimentation separation device 22, centrifugal separation device 25, filtration device 28, etc.) temporarily stops operation, a certain period of time. The filtered water can be supplied to the bearing water tank 10. The filtered water may be circulated between the filtered water tank 36 and the filtering device 28 in order to further remove foreign matters from the filtered water stored in the filtered water tank 36. For this purpose, a return pipe L4 is connected to the filtered water tank 36, and the other end of the return pipe L4 joins the inlet side of the filtration device 28 of the first pipe L1. In order to control the circulation of filtered water, a valve 33 and a pump 34 are installed in the return pipe L4. The downstream end of the filtered water tank 36 of the second pipe L2 is connected to the bearing water tank 10. As a result, the second pipe L <b> 2 supplies filtered water to the bearing 9 and the shaft seal device 13 of the water turbine generator 1.

  The inventor of the present application investigated the wear situation of the main shaft in the existing turbine generator. The hydropower facility where the surveyed turbine generator is installed does not have a filtration device. When the filtered water in the bearing water tank was analyzed when the turbidity of the river water became high, transparent, white and brown minerals having a particle size of 0.5 mm or less were detected. Transparent minerals are considered to be mainly quartz, and white and brown minerals are mainly considered to be feldspar. Moreover, many crushed mineral pieces adhered to the bearing and the shaft seal. These mineral pieces are also considered to be mainly quartz and feldspar.

  One of the causes of wear of the main shaft 2 is the particle size. The size of the gap 12 between the main shaft 2 and the bearing 9 is generally several tens of μm. However, since the main shaft 2 may be eccentric with respect to the bearing 9, the particle size is about twice as large as the size of the gap 12. Can enter the gap 12. For the same reason, a foreign substance having a particle diameter smaller than several tens of μm may enter the gap 12 and remain attached. For these reasons, it is considered that wear of the main shaft 2 can be suppressed by removing foreign matters having a particle size of about 5 to 75 μm. That is, foreign matter having a particle size of less than 5 μm is less likely to remain even if it enters the gap 12, and foreign matter having a particle size of more than 75 μm is less likely to enter the gap 12. Absent. FIG. 3 shows a measurement example of the particle size distribution of the foreign matter contained in the outlet water of the centrifugal separator 25 provided in the existing water turbine generator, and FIG. 4 shows the observation result of the outlet water using an optical microscope. . A sedimentation separation facility 22 is provided upstream of the centrifugal separation facility 25. In FIG. 4, one scale is 100 μm, and a dark portion indicates a portion where foreign matter having a particle size of about 5 to 75 μm is present, and a slightly dark portion having a slightly dark color collects fine particles. The part which is doing is shown. From the above, it was confirmed that foreign matters having a particle size of about 5 to 75 μm are difficult to remove with the existing centrifugal separation equipment 25 and sedimentation separation equipment 22.

  Since the foreign matter having a particle size of about 5 to 75 μm has a small mass, the centrifugal force that acts during centrifugation is reduced. As a result, it was confirmed that the water could not be separated well and remained in the outlet water. In the past, water turbine generators have removed foreign substances in the final stage from a foreign substance having a small particle size by means of a centrifugal separation device 25. However, the effect of reducing wear caused by foreign substances, which is a problem of the present invention, is not satisfactory. Confirmed that it was enough.

  Another cause of wear of the main shaft 2 is the hardness of the foreign matter. When the hardness of the foreign matter exceeds the hardness of steel (steel) which is the material of the main shaft 2, the main shaft 2 is easily damaged by the foreign matter. Steel has a Mohs hardness of 5-6, feldspar has a Mohs hardness of 6, and quartz has a Mohs hardness of 7. Therefore, the type of foreign matter that contributes to the wear of the main shaft 2 is considered to be mainly quartz and then feldspar from the viewpoint of Mohs hardness.

  From the above, the filtration device 28 is not particularly limited as long as it can remove foreign matters that cause abrasion of the main shaft 2 contained in the raw water, and is a sand filtration device or a microfiltration membrane device equipped with an inorganic membrane or an organic membrane (the pore size is An approximate microfiltration membrane device (having a pore diameter of approximately 0.01 to 0.001 μm) can be used. Moreover, it is desirable that the filtration device 28 has a performance of removing at least a part of foreign matters having a particle diameter of 5 to 75 μm and a Mohs hardness of 6 or more contained in raw water. As a result of the analysis, it has been found that a foreign substance having a particle size of 75 μm or less contains a large number of quartz particles. By removing particles having a particle size of 5 to 75 μm, the quartz particles are effectively removed. can do. From the above viewpoint, the filtration device 28 that can be suitably used is a sand filtration device. The sand filtration device is a filtration device in which a particulate filter medium is filled with a single layer or multiple layers, and efficiently removes particles having a particle size of about 5 to 75 μm. Since a flow path through which water passes is formed between the particulate filter media, the pressure loss is also small. In the present invention, it is desirable that the filtration device 28 has a multilayer structure in which the entire filtration layer can be effectively used three-dimensionally in order to obtain a certain treated water quality. For example, by forming a filter medium having a small specific gravity and a large particle diameter and a filter medium having a large specific gravity and a small particle diameter, it is possible to effectively remove the particles from large particles to small particles in order. Particles having a particle size of 5 to 75 μm are called silt in the classification of earth and sand and have a charge on the surface, but a particle is formed by injecting a flocculant or the like before the filtration equipment 28 to neutralize the charge on the silt surface. Removal efficiency can also be improved by bonding and aggregating each other.

  A backwash pipe L5 branched from the return pipe L4 and connected to the filter apparatus 28 is provided for backwashing of the filtration apparatus 28. A valve 32 for controlling the flow of filtered water is provided on the backwash pipe L5. The trapped foreign matter can be removed from the filtering device 28 by supplying the filtered water stored in the filtering water tank 36 to the filtering device 28 in the direction opposite to the flow of normal raw water. Since sand filter generally has little sudden increase in differential pressure, the frequency of backwashing can be reduced. In order to determine the necessity of backwashing, a differential pressure gauge 29 for measuring the differential pressure on the inlet side and the outlet side of the filtration device 28 is provided, and the differential pressure measured by the differential pressure gauge 29 exceeds a certain value. If this happens, backwashing can be performed. In addition, by automatically switching the backwash frequency from the differential pressure increase rate (the differential pressure increase rate with respect to a predetermined time), the cooling water can be stably and continuously supplied without causing a flow rate decrease due to the differential pressure increase. it can. For example, the backwash frequency is increased when the differential pressure increase rate is increased, and the backwash frequency is decreased when the differential pressure increase rate is decreased. Specifically, as shown in FIG. 5, when the normal pressure increase rate is 40 kPa / day and the backwash frequency is once / day, the differential pressure increase rate is 60 kPa / day. The backwash frequency is set to 2 times / day, and when the differential pressure increase rate reaches 80 kPa / day, the backwash frequency is controlled to be 3 times / day.

  In the present invention, in order to stably supply the cooling water continuously, it is possible to provide means for partially or selectively washing the filtration layer having a large amount of detention while continuing the water flow. For example, a cleaning pipe and a cleaning drain pipe are provided so that the surface layer part of the filtration layer with a large amount of detention can be cleaned, and the cleaning water is supplied from the cleaning pipe while performing the filtration water flow without stopping the water flow. Wash.

  When the content of foreign matter in the raw water is small, a part or all of the raw water can be supplied to the turbine generator 1 without passing through the filtering device 28. For this purpose, the first pipe L1 is provided with a first measuring means 39 (sensor) for measuring the particle size distribution of foreign matter in the raw water. Moreover, the 1st valve 26 is provided between the branch part of the bypass piping L3 of the 1st piping L1, and the filtration apparatus 28, and the 2nd valve 27 is provided on the bypass piping L3. Based on the particle size distribution measured by the sensor 39, the control means 38 controls the opening degrees of the first valve 26 and the second valve 27. Normally, the first valve 26 is fully open and the second valve 27 is fully closed, and the entire amount of raw water is passed through the filtration device 28. When the control means 38 determines that the above-mentioned particles having a particle diameter of 5 to 75 μm are hardly contained in the raw water, the first valve 26 is fully closed and the second valve 27 is fully opened to bypass the entire amount. To do. Depending on the particle size distribution measured by the sensor 39, the opening degree of the first valve 26 and the second valve 27 may be adjusted so that only a part of the raw water exiting the centrifugal separator 25 passes through the bypass pipe L3. . The turbidity, chromaticity, or differential pressure of the raw water may be measured instead of or in addition to the particle size distribution of the foreign material. Further, in order to quantitatively monitor the gap 12 between the main shaft 2 and the bearing 9, second measuring means 40 for measuring the pressure in the bearing water tank 10, more specifically, at least one of the bearing 9 and the shaft seal device 13 is used. (Sensor) is provided (see FIG. 1). When the pressure drop is detected by the sensor 40, it indicates that the gap is increased due to wear, that is, the gap 12 is increased. By combining the sensor 40 and the above-described sensor 39, the numerical value of the particle size distribution of the sensor 39 for judging the total amount processing or the bypass processing is corrected from the measurement result of the sensor 40, and the operation is changed to an effective operation for reducing wear. Can do.

  In order to improve the lubrication performance of the bearing 9, the viscosity of filtered water can be increased. Water used as a bearing lubricant in a water-lubricated turbine generator has a much lower kinematic viscosity than turbine oil used as a bearing lubricant in an oil-lubricated turbine generator. For this reason, there is a possibility that sufficient lubricity and water film thickness may not be obtained during starting / stopping and low-speed rotation, and compared with oil-lubricated water turbine generators, Seizure is likely to occur. Therefore, it is desirable that the filtered water used as a bearing lubricant in a water-lubricated water turbine generator has better sliding characteristics and self-lubricating properties. For this purpose, a chemical solution injection device 37 for injecting a chemical solution for increasing the viscosity of the filtered water is connected to the second pipe L2. For example, xanthan gum can be used as the chemical solution. Xanthan gum is a thickener that gives viscosity to the liquid and increases the thickness of the water film formed in the gap 12 of the bearing 9. Xanthan gum consists of polysaccharides made from microorganisms that inhabit the soil, so even if it is discharged into the river as it is, the burden on the environment is small. However, in this embodiment, in order to efficiently use xanthan gum, a return pipe L6 is provided to return the filtered water heated by the bearing 9 to the first pipe L1, and the filtered water containing xanthan gum is circulated. Can do. In order to cool the filtered water heated through the bearing 9, a cooling device 35 for the filtered water is provided on the return pipe L6. The outlet water of the centrifugal separator 25 can be used as a heat source for cooling the filtered water during the circulating operation of the filtered water. In FIG. 2, a cooling water supply pipe L <b> 8 that connects the outlet of the centrifugal separator 25 and the cooling device 35 is provided. The outlet water of the centrifugal separator 25 having cooled the filtered water by the cooling device 35 can be discharged into the river.

  As described above, the hydroelectric power supply system 100 according to the present invention can remove foreign substances from the raw water that may be mixed in the bearings and shaft seals of the turbine generator in advance. Can be suppressed. Further, the liquid supply system 100 for hydroelectric power generation can be operated unattended. That is, the above-described total water flow operation, partial water flow operation, bypass operation, backwashing, circulation operation and the like can be automatically performed by the control means 38. For this reason, even if this system is introduced into a hydroelectric power generation facility that normally performs unmanned operation, the unmanned operation of the hydroelectric power generation facility is still possible.

Furthermore, the whole system can be reduced in size by using a filtration apparatus. In hydroelectric power generation facilities, it may be difficult to secure a flat site, and it may be difficult to install a sedimentation separator that requires a large flat area. In addition, since the foreign matter having a smaller particle size can be removed (sedimented) as the plane area of the sedimentation separator is larger, in order to remove the foreign matter having a particle size of 5 to 75 μm described in the embodiment, Although it is conceivable to enlarge the plane area, it may be difficult for the same reason. For example, when removing a foreign substance having a particle size of 10 μm with a sedimentation separator, if the raw water flow rate is 2 m ³ / h, the flat area is 4 m ² , and if the raw water flow rate is 12 m ³ / h, the sedimentation separation is 24 m ² . A device is required. In contrast, when using a sand filtration device as a filtering device, if the flow rate of raw water ^2m 3 / h of a plane area 0.4 m ^2, the flow rate of raw water ^12m 3 / if h planar area 2.4 m ² A sand filter is sufficient.

DESCRIPTION OF SYMBOLS 1 Turbine generator 2 Main shaft 9 Bearing 10 Bearing water tank 12 Gap 13 Shaft seal device 22 Sedimentation separator 25 Centrifugal separator 28 Filtration device 36 Filtration water tank 100 Liquid supply system for hydroelectric power generation L1 1st piping L2 2nd piping

Claims (14)

A filtration device for filtering raw water to produce filtered water from which at least a part of the foreign matter contained in the raw water has been removed;
A first pipe for connecting a raw water source to the filtration device and supplying raw water taken from the raw water source to the filtration device;
A liquid supply system for hydroelectric power generation, comprising: a second pipe that connects the filtration device to a turbine generator and supplies the filtrate to the turbine generator.   2. The liquid supply system for hydroelectric power generation according to claim 1, wherein the second pipe supplies the filtered water to a turbine wheel bearing or a water wheel shaft seal device of the water turbine generator.   The liquid supply system for hydroelectric power generation according to claim 1 or 2, wherein the filtering device removes at least a part of a foreign matter having a particle diameter of 5 to 75 µm and a Mohs hardness of 6 or more contained in the raw water.   The liquid supply system for hydroelectric power generation according to any one of claims 1 to 3, further comprising a chemical liquid injector connected to the second pipe and injecting a chemical liquid that increases the viscosity of the filtered water into the filtered water. . A return pipe for returning the filtered water heated by the turbine generator to the first pipe;
The liquid supply system for hydroelectric power generation according to any one of claims 1 to 4, further comprising: a cooling device for the filtered water provided on the return pipe.   The liquid supply system for hydroelectric power generation according to any one of claims 1 to 5, wherein the filtration device is a sand filtration device, a microfiltration membrane device, or an ultrafiltration membrane device.   The liquid supply system for hydroelectric power generation according to any one of claims 1 to 5, wherein the filtration device is a sand filtration device including a granular filter medium filled with a single layer or multiple layers. The sand filtration device comprises a multi-layer granular filter medium,
The liquid supply system for hydroelectric power generation according to claim 7, further comprising a cleaning unit that partially or selectively cleans the layer having a large amount of retention of the granular filter medium while continuing water flow.   The liquid supply system for hydroelectric power generation according to any one of claims 1 to 8, further comprising a bypass pipe that branches off from the first pipe and bypasses the filtration device. A first valve located between the branch of the bypass pipe of the first pipe and the filtration device;
A second valve located on the bypass pipe;
A first measuring means provided in the first pipe for measuring the particle size distribution of the foreign matter in the raw water or the turbidity, chromaticity or differential pressure of the raw water; A second measuring means for measuring the pressure of the vehicle shaft seal device;
The liquid supply for hydropower generation according to claim 9, further comprising a control unit that controls an opening degree of the first valve and the second valve in accordance with a measurement result of the first and second measurement units. system. Filtering raw water taken from the raw water source to produce filtered water from which at least a portion of the foreign matter contained in the raw water has been removed;
Supplying the filtered water to the water turbine generator.   The method for supplying a liquid to a turbine generator according to claim 11, wherein at least a part of the foreign matter having a particle diameter of 5 to 75 µm and a Mohs hardness of 6 or more contained in the raw water is removed. Measuring the particle size distribution of the foreign matter in the raw water taken from the raw water source or the turbidity, chromaticity or differential pressure of the raw water;
And supplying at least a part of the raw water to the turbine generator without filtering according to a particle size distribution of the foreign matter or a measurement result of turbidity, chromaticity or differential pressure of the raw water. A method for supplying a liquid to the water turbine generator according to 11 or 12. Measuring the pressure of the turbine bearing of the turbine generator or the shaft seal device for turbine,
At least a part of the raw water is corrected by correcting the particle size distribution of the foreign matter or the measurement result of turbidity, chromaticity or differential pressure of the raw water according to the pressure measurement result of the bearing for water turbine or the shaft seal device for water turbine. The method for supplying liquid to the turbine generator according to claim 13, further comprising: supplying the turbine generator to the turbine generator without filtering.