JP7158129B2 - Liquid supply system for hydroelectric power generation and method for supplying liquid to water turbine generator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a liquid supply system for hydroelectric power generation and a liquid supply method for a hydraulic turbine generator, and more particularly to a liquid supply system for supplying liquid to a hydraulic turbine bearing or a hydraulic shaft seal device of the hydraulic 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 system has the risk of polluting 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 the bearings and is capable of avoiding the above risk is sometimes adopted.

In the water lubrication system, river water is directly used as a lubricating material for the bearing, so it is necessary to prevent foreign matter from entering the sliding portion of the bearing. Patent Document 1 discloses a liquid supply system with sedimentation and centrifugation equipment.

Patent No. 4628252 specification

In recent years, due to the effects of climate change, it is becoming easier for short-term torrential rains to occur. Sudden volcanic eruptions can also cause ejecta to flow into rivers. For this reason, the properties of foreign matter in river water change, and it is difficult to prevent foreign matter from entering the bearings only with sedimentation separation equipment and centrifugal separation equipment. Sedimentation equipment separates contaminants by the difference in sedimentation speed, and centrifugal separation equipment separates them by the difference in angular momentum acting by rotation. This is because there is a problem in principle. As a result, when the turbidity of the river is high, power generation must be interrupted or stopped to prevent wear, and if power generation continues, the main shaft of the water turbine tends to wear due to foreign matter entering the bearings. As a result, the frequency of large-scale repair and replacement work tends to increase. A small gap is also provided between the shaft sealing portion of the bearing water tank that houses the bearing and the main shaft, and if foreign matter enters the gap, the main shaft will wear out.

In addition, while the water turbine generator is in operation, it is necessary to continuously supply cooling water to the main shaft and bearings. There was a problem that it could not be stably and continuously supplied.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid supply system for hydroelectric power generation that can reduce wear due to foreign matter on the main shaft of a water turbine generator and that can stably and continuously supply cooling water having a certain quality of treated water. .

The liquid supply system for hydroelectric power generation of the present invention includes a filtration device that filters raw water to produce filtered water from which at least a portion of foreign matter contained in the raw water is removed; A first pipe that supplies raw water taken in to the filtration device, and a second pipe that connects the filtration device to the hydraulic turbine generator and supplies filtered water to the turbine bearing of the hydraulic turbine generator or the hydraulic turbine shaft seal device. and a plumbing. The filtering device is a sand filtering device, a microfiltration membrane device, or an ultra-microfiltration membrane device, and removes at least part of foreign substances having a particle size of 5 to 75 μm and a Mohs hardness of 6 or more contained in the raw water.
In one aspect, the liquid supply system for hydroelectric power generation includes a chemical injection device connected to the second pipe for injecting into the filtered water a chemical that increases the viscosity of the filtered water. In another aspect, a hydroelectric liquid supply system includes a return line returning filtered water heated by a hydro-turbine generator to a first line, and a chiller for the filtered water on the return line. ing. In yet another aspect, the hydroelectric liquid supply system includes a bypass line branching from the first line and bypassing the filtration device.

According to the present invention, since at least part of the foreign matter contained in the raw water is removed by the filtering device, it is possible to provide a hydraulic power generation liquid supply system capable of reducing abrasion caused by the foreign matter on the main shaft of the water turbine generator. can.

1 is a schematic configuration diagram of a water turbine generator to which the present invention is applied; FIG. 1 is a schematic configuration diagram of a liquid supply system for hydroelectric power generation according to an embodiment of the present invention; FIG. It is an example of measurement of the particle size distribution of foreign matter contained in centrifugal separator outlet water. It is an example of observation with an optical microscope of centrifugal separator outlet water. It is an example of backwash operation according to the rate of increase in differential pressure.

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 illustrates the concept of a hydroelectric liquid supply system (hereinafter referred to as system 100).

Referring to Figure 1, a hydro-turbine generator 1 has a main shaft 2 on which a runner 3 is mounted. The runner 3 is housed in a casing 5 connected to a penstock 4 (see FIG. 2). A generator 7 is attached to the upper end of the main shaft 2 via a coupling 6 . The river water supplied from the penstock 4 rotates the runner 3 inside the casing 5 to generate electricity by the generator 7 . The penstock 4 is provided with an inlet valve 8 (see FIG. 2) for stopping the supply of river water during maintenance of the hydraulic turbine generator 1 .

The main shaft 2 is supported by an underwater bearing (hereinafter referred to as bearing 9). The bearing 9 is housed in a bearing water tank 10 . The bearing 9 is a sliding bearing, and a small gap 12 is provided between a collar 11 attached to the main shaft 2 and a sliding surface 9a of the bearing 9. As shown in FIG. The bearing water tank 10 is filled with river water, and the river water flowing into the gap 12 lubricates the bearings 9 and cools the bearings 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 flows continuously from the supply pipe (second pipe L2) to the bearing water tank 10. , and the river water whose temperature has risen is continuously discharged from the bearing water tank 10 into the river. A shaft sealing device for a water turbine (hereinafter referred to as a shaft sealing device 13) is provided in the penetrating portion of the main shaft 2 of the bearing water tank 10. As shown in FIG. The shaft seal device 13 prevents leakage of river water in the bearing water tank 10 .

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

The system 100 has a filtering device 28 for filtering raw water. At least 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 hydro turbine generator 1 are accommodated. The filtering device 28 is connected to the raw water source 4 by a first pipe L1 and 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 filtering device 28 through the first pipe L1 to be filtered water, and the filtered water is supplied to the bearing water tank 10 through the second pipe L2. A desalting device 30 is provided downstream of the filtering device 28 . As the desalting device, for example, a cartridge polisher filled with an ion exchange resin can be used. By removing the ionic components contained in the filtered water, the main shaft 2 can be prevented from rusting.

A sedimentation separation device 22 is provided along the first pipe L1. The sedimentation separation device 22 sediments and removes foreign matter with a relatively large particle size by gravity. A valve 21 is provided between the sedimentation separator 22 and the raw water source 4 . Closing the valve 21 prevents raw water from flowing into the sedimentation device 22 during maintenance of the sedimentation device 22 .

A strainer 23 is provided downstream of the sedimentation separation device 22 in the first pipe L1, and removes relatively large-sized foreign matter that has not been separated by the sedimentation separation device 22 . A centrifugal separator 25 is provided downstream of the strainer 23 of the first pipe L1. The centrifugal separation device 25 separates, by the centrifugal action, foreign substances having a specific gravity greater than 1, which is the specific gravity of water, and which could not be removed by the strainer 23 . The separated foreign matter is discharged into a river through a pipe. A valve 24 is provided on the inlet side of the centrifuge 25 . Closing the valve 24 prevents raw water from entering the centrifuge 25 during maintenance of the centrifuge 25 .

A bypass line L3 branches from the first line L1 downstream of the centrifugal separator 25 of the first line L1. The bypass pipe L3 bypasses the filtration device 28 and is connected to a filtration water tank 36, which will be described later. The downstream end of the centrifugal separator 25 of the first pipe L1 is connected to the filtering device 28 .

A filtering water tank 36 is provided via a valve 31 downstream of the filtering device 28 in the second pipe L2. The filtered water tank 36 stores filtered water filtered by the filtering device 28 . As a result, even if the supply amount of raw water fluctuates, or if 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 operating, , filtered water can be supplied to the bearing water tank 10 . In order to further remove foreign matter from the filtered water stored in the filtered water tank 36 , the filtered water may be circulated between the filtered water tank 36 and the filtering device 28 . For this purpose, a return pipe L4 is connected to the filter water tank 36, and the other end of the return pipe L4 merges with the inlet side of the filter device 28 of the first pipe L1. A valve 33 and a pump 34 are installed in the return line L4 to control the circulation of filtered water. The downstream end of the filtering water tank 36 of the second pipe L2 is connected to the bearing water tank 10 . As a result, the second pipe L2 supplies the 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 condition of the main shaft in the existing water turbine generator. The hydropower facilities where the hydro turbine generators of the survey target are installed are not equipped with filtration equipment. 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 with a particle size of 0.5 mm or less were detected. Clear minerals are believed to be primarily quartz, and white and brown minerals are primarily considered to be feldspars. In addition, a large number of crushed mineral fragments were attached to the bearing and shaft seal. These mineral fragments are also believed to be mainly quartz and feldspar.

One of the causes of wear of the spindle 2 is grain size. The dimension of the gap 12 between the spindle 2 and the bearing 9 is generally several tens of μm. foreign matter can enter the gap 12 . For the same reason, foreign matter with a particle size smaller than several tens of micrometers may enter the gap 12 and remain there. For these reasons, it is considered that the wear of the main shaft 2 can be suppressed by removing foreign matter having a particle size of approximately 5 to 75 μm. That is, foreign matter with a particle diameter of less than 5 μm is less likely to remain even if it enters the gap 12, and foreign matter with a particle diameter of more than 75 μm is less likely to enter the gap 12, so these foreign matter are not important to the present invention. do not have. In addition, FIG. 3 shows an example of measurement of the particle size distribution of foreign matter contained in the outlet water of the centrifugal separation equipment 25 provided in the existing water turbine generator, and FIG. 4 shows the observation results of the outlet water with an optical microscope. . A sedimentation separation facility 22 is provided on the upstream side of the centrifugal separation facility 25 . In FIG. 4, one scale is 100 μm, and the darker color indicates the portion where foreign matter with a particle size of about 5 to 75 μm is present. indicates the part where From the above, it was confirmed that the existing centrifugal separation equipment 25 and sedimentation separation equipment 22 are difficult to remove foreign matter with a particle size of about 5 to 75 μm.

Foreign matter with a particle size of about 5 to 75 μm has a small mass, so that the centrifugal force acting on it is small during centrifugation. As a result, it was confirmed that the separation from water was not successful and remained in the outlet water. Until now, in the water turbine generator, the centrifugal separation equipment 25 has been used to remove foreign matter with a small particle size in the final stage, but the effect of reducing wear due to foreign matter, which is the subject of the present invention, is insufficient. Confirmed to be sufficient.

Another cause of wear of the spindle 2 is the hardness of foreign matter. If the hardness of the foreign matter exceeds the hardness of steel, which is the material of the spindle 2, the spindle 2 is likely to be 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, from the viewpoint of Mohs' hardness, the foreign matter that contributes to the wear of the main shaft 2 is mainly quartz, followed by feldspar.

From the above, the filtering device 28 is not particularly limited as long as it can remove foreign substances contained in the raw water that cause wear of the main shaft 2, and is a sand filtering device, a microfiltration membrane device equipped with an inorganic membrane or an organic membrane (pore diameter is approximately 0.05 to 10 μm), or an ultra-microfiltration membrane device (pore size approximately 0.01 to 0.001 μm). Moreover, it is desirable that the filtering device 28 has the ability to remove at least part of the foreign substances with a particle size of 5 to 75 μm and a Mohs hardness of 6 or more contained in the raw water. As a result of analysis, it has been found that many quartz particles are contained in foreign matter with a particle size of 75 μm or less, and removing particles with a particle size of 5 to 75 μm effectively removes quartz particles can do. From the above point of view, the filter device 28 that can be preferably used is a sand filter device. A sand filter is a filtration device filled with granular filter media in a single layer or multiple layers, and efficiently removes particles with a particle size of about 5 to 75 μm. Pressure loss is also small because channels through which water passes are formed between the granular filter media. In the present invention, in order to obtain a constant quality of treated water, it is desirable that the filtration device 28 be a multi-layered structure that can effectively utilize the entire filtration layer three-dimensionally. For example, by forming a filter medium with a small specific gravity and a large particle size and a filter medium with a large specific gravity and a small particle size, particles can be effectively removed from larger particles to smaller particles. In addition, particles with a particle size of 5 to 75 μm are called silt in terms of classification of earth and sand, and have an electric charge on the surface. It is also possible to increase the removal efficiency by binding and aggregating them.

A backwashing pipe L5 branched from the return pipe L4 and connected to the filtering device 28 is provided for backwashing the filtering device 28 . A valve 32 for controlling the flow of filtered water is provided on the backwash pipe L5. By supplying the filtered water stored in the filtered water tank 36 to the filtering device 28 in a direction opposite to the normal flow of raw water, the trapped foreign matter can be removed from the filtering device 28 . The sand filter generally has less abrupt rise in differential pressure, so the frequency of backwashing can be reduced. In addition, in order to determine the necessity of backwashing, a differential pressure gauge 29 is provided to measure the differential pressure between the inlet side and the outlet side of the filtering device 28. When the differential pressure measured by the differential pressure gauge 29 exceeds a certain value, If so, it can be backwashed. In addition, by automatically switching the backwash frequency based on the differential pressure rise rate (rate of rise in differential pressure over a predetermined time period), cooling water can be stably and continuously supplied without causing a decrease in flow rate due to an increase in differential pressure. can. For example, the frequency of backwashing is increased when the rate of increase in differential pressure increases, and the frequency of backwashing is decreased when the rate of increase in differential pressure decreases. Specifically, as shown in FIG. 5, when the normal differential pressure increase rate is 40 kPa/day and the backwash frequency is set to 1 time/day, when the differential pressure increase rate is 60 kPa/day, , the backwashing frequency is set to 2 times/day, and when the differential pressure rise rate reaches 80 kPa/day, the backwashing frequency is controlled to be 3 times/day.

Further, in the present invention, in order to stably and continuously supply cooling water, it is also possible to provide a means for partially or selectively washing the filtration layer with a large retention amount while continuing water flow. For example, a cleaning pipe and a cleaning drainage pipe are provided so that the surface layer of the filtration layer with a large amount of retention can be washed, and while filtering water is being passed, washing water is supplied from the washing pipe to partially clean the surface without stopping the water flow. Wash.

If the content of foreign substances in the raw water is small, part or all of the raw water can be supplied to the hydro-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 substances in the raw water. A first valve 26 is provided between the branch of the bypass pipe L3 and the filtering device 28 of the first pipe L1, and a second valve 27 is provided on the bypass pipe 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, the second valve 27 is fully closed, and the entire amount of raw water is passed through the filtering device 28 . When the control means 38 determines that the raw water contains almost no particles with a particle size of 5 to 75 μm, the first valve 26 is fully closed and the second valve 27 is fully opened to bypass the entire amount. do. Depending on the particle size distribution measured by the sensor 39, the opening degrees of the first valve 26 and the second valve 27 may be adjusted so that only a portion of the raw water exiting the centrifugal separator 25 passes through the bypass pipe L3. . Instead of or in addition to the particle size distribution of foreign matter, turbidity, chromaticity or differential pressure of raw water may be measured. Also, in order to quantitatively monitor the gap 12 between the spindle 2 and the bearing 9, a 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 sealing device 13. (sensor) is provided (see FIG. 1). A pressure drop detected by the sensor 40 indicates that the gap is widening due to wear, ie, the gap 12 is increasing. By combining the sensor 40 and the above-described sensor 39, the numerical value of the particle size distribution of the sensor 39, which determines full amount processing or bypass processing from the measurement result of the sensor 40, is corrected, and the operation is changed to an effective operation for reducing wear. can be done.

In order to improve the lubricating performance of the bearing 9, the viscosity of the filtered water can be increased. Water, which is used as a lubricant for bearings in water-lubricated water turbine generators, has much lower kinematic viscosity than turbine oil, which is used as a lubricant for bearings in oil-lubricated turbine generators. For this reason, there is a possibility that sufficient lubricity and water film thickness cannot be obtained during start/stop and low-speed rotation, and compared to oil-lubricated water turbine generators, there is less wear and tear on the sliding surfaces of the bearings. Seizure is likely to occur. Therefore, it is desirable that filtered water used as a lubricant for bearings in water-lubricated water turbine generators has better sliding properties and self-lubricating properties. For this purpose, a chemical injection device 37 for injecting a chemical for increasing the viscosity of filtered water is connected to the second pipe L2. For example, xanthan gum can be used as the chemical solution. Xanthan gum is a thickening agent that gives viscosity to the liquid and increases the thickness of the water film formed in the gap 12 of the bearing 9 . Since xanthan gum is composed of polysaccharides produced by microorganisms living in the soil, even if it is directly discharged into rivers, the burden on the environment is small. However, in this embodiment, in order to use xanthan gum efficiently, 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 be done. A filtered water cooling device 35 is provided on the return line L6 to cool the filtered water heated through the bearing 9 . Outlet water of the centrifugal separator 25 can be used as a heat source for cooling the filtered water during circulation operation of the filtered water. In FIG. 2, a cooling water supply pipe L8 connecting the outlet of the centrifugal separator 25 and the cooling device 35 is provided. The outlet water of the centrifugal separator 25 which cooled filtered water with the cooling device 35 can be discharged|emitted to a river.

As described above, the liquid supply system 100 for hydroelectric power generation of the present invention can remove foreign matter from the raw water in advance that may enter the bearings and shaft seals of the water turbine generator, thereby reducing the wear of the main shaft. can be suppressed. Also, the hydroelectric liquid supply system 100 is capable of unattended operation. In other words, the control means 38 can automatically perform all of the above-described full water flow operation, partial water flow operation, bypass operation, backwashing, circulation operation, and the like. For this reason, even if this system is introduced into hydroelectric power facilities that normally operate unmanned, unmanned operation of the hydroelectric power facilities can continue.

Furthermore, the size of the entire system can be reduced by using the filtering device. It may be difficult to secure a flat site for a hydroelectric power plant, and it may be difficult to install a sedimentation separator that requires a large flat area. In addition, since the larger the flat area of the sedimentation device, the smaller the particle size foreign matter can be removed (settled), in order to remove the foreign matter with a particle size of 5 to 75 μm described in the embodiment, the existing sedimentation device Enlarging the plane area is also conceivable, but may be difficult for similar reasons. For example, when removing foreign matter with a particle size of 10 μm with a sedimentation separation device, if the flow rate of raw water is 2 m ³ /h, the plane area is 4 m ² , and if the flow rate of raw water is 12 m ³ /h, the plane area is 24 m ² . equipment is required. On the other hand, when a sand filter is used as a filter, the flat area is 0.4 m ² if the raw water flow rate is 2 m ³ /h, and the flat area is 2.4 m ² if the raw water flow rate is 12 m ³ /h. sand filter equipment is sufficient.

1 Hydro Turbine Generator 2 Main Shaft 9 Bearing 10 Bearing Water Tank 12 Gap 13 Shaft Seal Device 22 Sedimentation Separation Device 25 Centrifugal Separator 28 Filtration Device 36 Filtration Water Tank 100 Liquid Supply System for Hydraulic Power Generation L1 First Pipe L2 Second Pipe

Claims (10)

a filtration device that filters raw water to produce filtered water from which at least a portion of foreign matter contained in the raw water has been removed;
a first pipe that connects a raw water source to the filtering device and supplies raw water taken from the raw water source to the filtering device;
a second pipe that connects the filtering device to a water turbine generator and supplies the filtered water to a water turbine bearing or a water turbine shaft sealing device of the water turbine generator;
a chemical injection device that is connected to the second pipe and injects into the filtered water a chemical that increases the viscosity of the filtered water ;
The filtration device is a sand filtration device, a microfiltration membrane device, or an ultra microfiltration membrane device, and removes at least part of foreign substances with a particle size of 5 to 75 μm and a Mohs hardness of 6 or more contained in the raw water, for hydroelectric power generation. liquid supply system. a filtration device that filters raw water to produce filtered water from which at least a portion of foreign matter contained in the raw water has been removed;
a first pipe that connects a raw water source to the filtering device and supplies raw water taken from the raw water source to the filtering device;
a second pipe that connects the filtering device to a water turbine generator and supplies the filtered water to a water turbine bearing or a water turbine shaft sealing device of the water turbine generator;
a return pipe that returns the filtered water heated by the water turbine generator to the first pipe;
and the filtered water cooling device provided on the return pipe ,
The filtration device is a sand filtration device, a microfiltration membrane device, or an ultra microfiltration membrane device, and removes at least part of foreign substances with a particle size of 5 to 75 μm and a Mohs hardness of 6 or more contained in the raw water . liquid supply system. 3. A liquid supply system for hydroelectric power generation according to claim 1 or 2 , wherein the filter device is a sand filter device with granular filter media packed in a single layer or multiple layers. The sand filter device comprises multiple layers of granular filter media,
4. A liquid supply system for hydroelectric power generation according to claim 3 , comprising washing means for partially or selectively washing the high retention layer of said particulate filter media while continuing to pass water. a filtering device that filters raw water to produce filtered water from which at least a portion of foreign matter contained in the raw water has been removed;
a first pipe that connects a raw water source to the filtering device and supplies raw water taken from the raw water source to the filtering device;
a second pipe that connects the filtering device to a water turbine generator and supplies the filtered water to a water turbine bearing or a water turbine shaft sealing device of the water turbine generator;
a bypass pipe that branches from the first pipe and bypasses the filtering device ;
The filtration device is a sand filtration device, a microfiltration membrane device, or an ultra microfiltration membrane device, and removes at least a part of foreign substances having a particle size of 5 to 75 μm and a Mohs hardness of 6 or more contained in the raw water, for hydroelectric power generation. liquid supply system. a first valve positioned between a branching portion of the bypass pipe of the first pipe and the filtering device;
a second valve located on the bypass pipe;
A first measuring means provided in the first pipe and measuring the particle size distribution of the foreign matter in the raw water or the turbidity, chromaticity or differential pressure of the raw water, and the hydraulic bearing of the hydraulic turbine generator or the water a second measuring means for measuring the pressure of the vehicle shaft sealing device;
6. The liquid supply for hydroelectric power generation according to claim 5 , further comprising control means for controlling opening degrees of said first valve and said second valve according to measurement results of said first and second measurement means. system. Claims 1 to 6 , comprising at least one of a sedimentation separation tank provided upstream of the filtering device in the first pipe and a centrifugal separation device provided upstream of the filtering device in the first pipe A liquid supply system for hydroelectric power generation according to any one of Claims 1 to 3. 8. A liquid supply system for hydroelectric power generation according to any one of claims 1 to 7 , comprising a filtering water tank provided downstream of said filtering device in said second pipe. Filtering raw water taken from a raw water source to produce filtered water from which at least a portion of foreign matter contained in the raw water has been removed;
supplying the filtered water to a water turbine bearing or a water turbine shaft seal device of a water turbine generator,
When making the filtered water, at least part of the foreign matter with a particle size of 5 to 75 μm and a Mohs hardness of 6 or more contained in the raw water is removed by a sand filter device, a microfiltration membrane device, or an ultra microfiltration membrane device ,
measuring the particle size distribution of the foreign matter or the turbidity, chromaticity or differential pressure of the raw water in the raw water taken from the raw water source;
The water turbine bearing of the water turbine generator or the water turbine without filtering at least a part of the raw water according to the particle size distribution of the foreign matter or the measurement result of the turbidity, chromaticity or differential pressure of the raw water and supplying a shaft sealing device . measuring the pressure of the water turbine bearing or the water turbine shaft seal device of the water turbine generator ;
According to the pressure measurement result of the water turbine bearing or the water turbine shaft sealing device, the particle size distribution of the foreign matter or the measurement result of the turbidity, chromaticity or differential pressure of the raw water is corrected, and at least one of the raw water 10. A method of supplying liquid to a water turbine generator according to claim 9 , comprising supplying the liquid to the water turbine bearing or the water turbine shaft seal device of the water turbine generator without filtering the water turbine generator.

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