Maintenance flow rate adjustment method and maintenance flow rate adjustment system

Abstract

To provide a maintained flow-rate adjustment method with which water intake amount for hydroelectric power generation can be increased while ensuring the maintained flow-rate when taking in water from the water intake gate for hydroelectric power generation at the dam and discharging the maintained flow-rate from the discharge gate to the downstream side of the dam.SOLUTION: A maintained flow-rate adjustment method includes a cut-off weir 3 of a dam 2, a hydroelectric power generation water intake gate 4 that takes in water used in a hydroelectric power generation facility 13 located far from the dam 2, a discharge gate 5 for discharging water to a downstream side 12 of the dam 2 and a sand discharge gate 6 provided in the cutoff weir 3, and includes a sand discharge gate opening process of increasing the opening of the sand discharge gate 6 at desired intervals until the sum F of a discharge amount F1 from the discharge gate 5 and a discharge amount F2 from the sand discharge gate 6 reaches a maintenance flow-rate M when a water level L falls below a water level L0, when water is taken in from the water intake gate 4 for hydroelectric power generation and discharged to the downstream side 12 from the discharge gate 5 and when the water level L of the dam 2 required to secure the maintained flow-rate M on the downstream side 12 is the water level L0.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a maintenance flow rate adjustment method and maintenance flow rate adjustment system that can increase the amount of water taken for hydroelectric power generation while ensuring the maintenance flow rate when taking water from a dam through a hydroelectric power generation intake gate and discharging the maintenance flow rate from a discharge gate downstream of the dam.

[0002] First, the problems with the conventional technology will be described with reference to FIGS. Fig. 13 is an image of a dam. Fig. 14 is an image of water discharged from the dam shown in Fig. 13. 13, a dam 50 to which the present invention is applicable comprises a stop weir 3 that holds back water, a hydroelectric power generation intake gate 4 that is installed at the stop weir 3 and takes in water to be used at a hydroelectric power generation facility 13 located far from the dam 50, a discharge gate 5 that is also installed at the stop weir 3 and discharges water downstream 12, and a sand flushing gate 6 that is also installed at the stop weir. The water taken in from the hydroelectric power generation intake gate 4 is supplied to the hydroelectric power generation facility 13 through a water passage 14.

[0003] Also, for example, as shown in FIG. 13, there are cases where water used for power generation at a hydroelectric power generation facility 13 located far from a dam 50 is discharged downstream 12' at a location far from the dam 50, or discharged into another river (not shown). In such a case, in the dam 50, the discharge water F that is taken in through the hydroelectric power generation intake gate 4, used in the hydroelectric power generation facility 13, and then discharged is 3 [m 3 / s] is the maintenance flow rate M [m 3 / s]. "Maintenance flow rate" refers to the minimum amount of water required to maintain the various functions of a river, such as ensuring the water depth necessary for river navigation or maintaining the habitat of aquatic organisms. In other words, when taking water from a river, it is necessary to take water while keeping the water flow rate of the river above the maintenance flow rate. In other words, the minimum discharge volume F released from Dam 50 L [m 3 / s] is the maintenance flow rate M [m 3 / s]. For this reason, in the dam 50 shown in FIG. 13, the water F used for power generation in the hydroelectric power generation facility 13 is 3 In addition, it is necessary to continue discharging a maintenance flow rate M to the downstream 12 side. Generally, the maintenance flow rate M is discharged to the downstream 12 side from a discharge gate 5 (for example, a fishway) provided in a cutoff weir 3 of a dam 50 .

[0004] Furthermore, there may be another dam equipped with a different hydroelectric power generation facility located upstream of the dam 50 shown in Fig. 13. In this case, when the discharge from the other dam to the dam 50 shown in Fig. 13 (e.g., discharge associated with power generation) is stopped in an emergency (tripped), the water level L [m] of the dam 50 drops suddenly. In such a case, in the dam 50 shown in FIG. 13, the intake water volume F from the intake gate 4 for hydroelectric power generation is set to 1000 m to ensure the maintenance flow rate M to the downstream 12 side. 3 needs to be restricted. However, there have been cases where the operation of the drive mechanism of the hydroelectric power generation water intake gate 4 is slow, or the drive mechanism has become worn out, making it difficult to quickly close the hydroelectric power generation water intake gate 4.

[0005] In preparation for such a situation, in the dam 50 shown in FIG. 13, the water level L of the dam 50 is set to a maintenance flow rate M (=M L ) required water level L 0 [m] significantly higher than the operational water level L P By maintaining the discharge volume F from the discharge gate 5 at [m], even if the discharge from another dam installed upstream of the dam 50 is stopped in an emergency and the closing operation of the hydroelectric power generation intake gate 4 cannot be performed immediately, the discharge volume F from the discharge gate 5 can be maintained. 1 [m 3 / s] is the maintenance flow rate M [m 3 / s]. In this case, as shown in FIG. 14, the maintenance flow rate M [m 3 / s] plus water level L P and water level L 0 Difference S X The corresponding water volume α [m 3 / s] is constantly discharged from the discharge gate 5, so the amount of water taken from the hydroelectric power generation intake gate 4 is F 3 had to be reduced. This has caused a problem that the power generation output of the hydroelectric power generation facility 13 in FIG. 13 cannot be increased.

[0006] One possible way to deal with this situation is to replace the hydroelectric power intake gate 4 at the dam 50 shown in FIG. 13, but due to the high equipment costs, this option is something that should be avoided as much as possible. For this reason, there was a need for technology that could effectively utilize existing facilities to increase the amount of water supplied to the hydroelectric power generation facility 13 while ensuring the maintenance flow rate M on the downstream 12 side of the dam 50. As prior applications in the technical field related to the present invention, for example, the following are known.

[0007] Patent document 1, titled “Method for regulating the amount of water discharged into a river from a discharge means in a water storage facility,” discloses an invention related to a method for regulating the amount of water discharged into a river from a discharge means in a water storage facility equipped with a water intake means for taking in a portion of the river water and a discharge means for constantly directly discharging a portion of the water into the river. The invention disclosed in Patent Document 1 is characterized in that, when the stored water level is higher than the upper threshold water level, a water level lowering control step is executed to lower the water level stored in the water storage facility so that this water level becomes a lowered target water level. Also, when the stored water level is lower than the lower threshold water level, a water level raising control step is executed to raise the water level stored in the water storage facility so that this water level becomes an raised target water level. The raised target water level is set as a water level that is lower than the upper threshold water level and higher than the central water level by a first predetermined value that is a value equal to or greater than 0 (zero). Also, the lowered target water level is set as a water level that is higher than the lower threshold water level and lower than the central water level by a second predetermined value that is greater than the first predetermined value. According to the invention disclosed in Patent Document 1 as described above, it is possible to accurately respond to changes in the amount of water inflow into a water storage facility while ensuring the maintenance flow rate of the river, and also to increase the amount of water that can be taken from the river.

[0008] Patent document 2 discloses an invention titled "Dam sand flushing gate opening and closing control device" that is suitable for controlling the opening and closing of a dam sand flushing gate when a hydroelectric generator installed at a reverse regulation reservoir type hydroelectric power plant trips. The invention disclosed in Patent Document 2 was made by the same applicant as the present invention, and will be explained using the same symbols as those shown in Figure 2 in the document. This is a dam sand flushing gate opening and closing control device 10 for opening a dam sand flushing gate 6 to ensure a responsible discharge volume to a downstream river 7 when a hydroturbine generator 3 installed in a reverse regulation pond type hydroelectric power plant trips, and is equipped with a sand flushing gate opening calculation unit 15, a sand flushing gate opening deviation detection unit 16, and a sand flushing gate control unit 17 which function as dam sand flushing gate opening and closing control means for controlling the opening and closing of the dam sand flushing gate 6 based on an ALR setting value for controlling the opening and closing of the guide vanes of the hydroturbine generator 3 so as to ensure a responsible discharge volume when the hydroturbine generator 3 is operating when the hydroturbine generator 3 trips, and the dam water level, which is the water level of the reverse regulation pond 1 of the reverse regulation pond type hydroelectric power plant. According to the invention disclosed in Patent Document 2 having the above configuration, by controlling the opening and closing of the dam sand flushing gate based on the ALR setting value and the dam water level when the hydroelectric generator trips, it is possible to automatically ensure the responsible discharge volume into the downstream river when the hydroelectric generator trips and to significantly suppress fluctuations in the water level of the downstream river. Furthermore, according to the invention disclosed in Patent Document 2, when controlling the opening and closing of the dam sand flushing gate when the hydroelectric generator trips, it is possible to eliminate the need for operation by a controller at the control center, thereby improving the efficiency of work. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2016-75039 A [Patent Document 2] JP 2014-169590 A Summary of the Invention [Problem to be solved by the invention]

[0010] The invention disclosed in the above-mentioned Patent Document 1 is a technique premised on the premise that the opening and closing operation of the water intake means (corresponding to the hydroelectric power generation water intake gate 4 in the dam 50 shown in FIG. 13) can be performed smoothly. In addition, although it may be possible to solve the problem to be solved by the present application by taking into consideration the invention disclosed in Patent Document 1, in order to do so, it would be necessary to replace or renovate the hydroelectric power generation intake gate 4 installed in the water cut-off weir 3 of the dam 50 shown in Figure 13 above, which would result in a problem of increased capital investment.

[0011] According to the invention disclosed in Patent Document 2, when an emergency shutdown (trip) occurs at a hydroelectric power generation facility attached to a dam, it is possible to ensure a maintained flow rate (= responsible discharge rate) downstream of the dam. However, there is no disclosure, suggestion or mention whatsoever as to how to maintain the maintained flow rate downstream of the dam when an emergency shutdown (trip) occurs at another hydroelectric power generation facility attached to another dam upstream of the dam. Therefore, even if the invention disclosed in Patent Document 2 is taken into consideration, the problem to be solved by the present invention cannot be solved.

[0012] The present invention has been made in response to such conventional circumstances, and its purpose is to provide a maintenance flow rate adjustment method and maintenance flow rate adjustment system which, when water is taken in from a dam through a hydroelectric power generation intake gate and the necessary maintenance flow rate is discharged from a discharge gate to the downstream side of the dam, can ensure the maintenance flow rate to the downstream side of the dam without controlling the hydroelectric power generation intake gate in the event that the supply of water to the dam from the upstream side is stopped or the supply rate suddenly drops.

[0013] The first invention for solving the above problems is a method for adjusting a maintenance flow rate, which is a method for adjusting a maintenance flow rate in a dam that includes a cut-off weir that holds back water, a hydroelectric power generation intake gate that is installed at the cut-off weir and takes in water to be used in a hydroelectric power generation facility located far from the cut-off weir, a discharge gate that is installed at the cut-off weir and discharges water to the downstream side, and a sand flushing gate, in a case where water is taken in through the hydroelectric power generation intake gate and discharged to the downstream side from the discharge gate, and the water level L of the dam required to ensure the maintenance flow rate M on the downstream side is equal to or greater than the water level L 0 If the water level of the dam is L, 0 When the water level falls below 100m, the discharge volume from the discharge gate F 1 and discharge volume from the sand flushing gate F 2 The method is characterized by including a sand flushing gate opening step for gradually increasing the opening of the sand flushing gate until the combined value F of the above reaches the maintenance flow rate M. In the first aspect of the present invention having the above-mentioned configuration, the sand flushing gate opening step is performed when the water level L of the dam is equal to or lower than the water level L 0 When the discharge volume falls below , the sand discharge gate is gradually opened to release water from the gate, and the discharge volume from the gate is F 1 and discharge volume from the sand flushing gate F 2 The combined value F of the two is set to be equal to or greater than the maintenance flow rate M. As a result, in the first invention, the water level L of the dam is equal to the water level L 0Even if the flow rate falls below this value, the maintenance flow rate M to the downstream side can be secured without restricting the water intake from the hydroelectric power generation water intake gate, i.e., without closing the hydroelectric power generation water intake gate.

[0014] The second invention is the above-mentioned first invention, wherein the discharge amount F from the discharge gate is 1 and discharge volume from the sand flushing gate F 2 When the sum F of the above exceeds the maintenance flow rate M, the sand flushing gate closing step is provided for gradually decreasing the opening of the sand flushing gate until the sum F reaches the maintenance flow rate M. The second invention having the above configuration has the same effect as the first invention. Furthermore, in the second invention, the sand flushing gate closing step is performed when the sand flushing gate is gradually opened to secure the maintenance flow rate M and the discharge flow rate F from the discharge gate is small. 1 and discharge volume from the sand flushing gate F 2 When the combined value F exceeds the maintenance flow rate M, the sand flushing gate is gradually closed to prevent water exceeding the maintenance flow rate M from being discharged downstream. This has the effect of increasing the amount of water taken from the hydroelectric power generation intake gate as much as possible.

[0015] The third aspect of the present invention is the second aspect of the present invention, wherein the maintenance flow rate M is a lower limit value M 1 and the upper limit of the maintenance flow rate M 2 The discharge volume from the discharge gate is F 1 and discharge volume from the sand flushing gate F 2 The sum of these values ​​F is the lower limit of the maintenance flow rate M 1 and the upper limit of the maintenance flow rate M 2 The sand flushing gate is not operated when the following conditions are met: The third aspect of the invention having the above configuration has the same effect as the second aspect of the invention. In the third aspect of the invention, the maintenance flow rate M is set to a lower limit M 1 and the upper limit of the maintenance flow rate M 2 The total value F is the minimum flow rate M 1 and the upper limit of the maintenance flow rate M 2When the flow rate is below 100%, the sand flushing gate is not operated, which has the effect of relatively reducing the number of times the sand flushing gate is operated to ensure the maintenance flow rate M. In this case, the power required to drive the sand flushing gate can be saved.

[0016] The fourth invention is any one of the first to third inventions, wherein the water level L 0 Water level L higher than ΔL 1 is set, and the water level of the dam is set to L 1 This system is characterized by having a preparatory process for turning on the switch of the control mechanism that drives the sand discharge gate when the sand discharge gate reaches the predetermined value. The fourth invention having the above configuration has the same effect as the first to third inventions. Furthermore, since the fourth invention includes the above-mentioned preparation step, the water level L of the dam is not increased to the water level L 0 When the water level falls below this level, the sand flushing gate can be opened as quickly as possible. In this case, the water level of the dam is L 0 This reduces the time lag between when the level drops below the threshold and when the sand flushing gate actually operates. As a result, it is possible to effectively prevent the discharge flow rate F downstream of the dam from unintentionally falling below the maintenance flow rate M.

[0017] A fifth aspect of the present invention is the fourth aspect of the present invention, wherein the switch includes a water level indicator float switch and a relay, and when the water level L of the dam is equal to or lower than the water level L 1 When the water level of the dam reaches level L, the water level gauge float switch is turned "ON". 0 When the voltage drops below this level, the relay is turned "ON" to open the sand flushing gate. The fifth invention having the above configuration is a more specific specification of the fourth invention described above, and its operation is the same as that of the fourth invention.

[0018] The sixth invention is any one of the first to fifth inventions, wherein the upper limit H of the opening degree H of the sand flushing gate is L is set, and during the sand flushing gate opening process, the opening degree H of the sand flushing gate is set to the upper limit H LIf the level exceeds or is exceeded, an alarm is issued and the sand discharge gate is fully closed. The sixth invention having the above-mentioned configuration has the same effect as the first to fifth inventions. Furthermore, in the sixth invention, the opening degree H of the sand flushing gate is set to its upper limit H L The state where the discharge amount F exceeds or has exceeded the limit means that the adjustment of the discharge amount F by the opening and closing operation of the sand flushing gate has reached its limit. In this case, the opening and closing control of the sand flushing gate is terminated and the intake amount F from the hydroelectric power generation intake gate is 3 It is necessary to ensure the maintenance flow M downstream of the dam by reducing or stopping the flow. On the other hand, if the sand discharge gate is opened indefinitely and water is released downstream of the dam without controlling (closing) the hydroelectric power intake gate, the water supply from the hydroelectric power intake gate to the hydroelectric power generation equipment downstream may suddenly be cut off. In this case, there is a risk of the hydroelectric power generation equipment downstream of the hydroelectric power generation intake gate undergoing an emergency shutdown (tripping), which would disrupt smooth power generation. Therefore, in the sixth aspect of the present invention, the opening degree H of the sand discharge gate is set to the upper limit H L If the level exceeds or is exceeded, an alarm is sounded and the sand flushing gate is fully closed, making it possible to smoothly shut down or limit the output of the hydroelectric power generation equipment downstream of the hydroelectric power generation water intake gate. Therefore, according to the sixth aspect of the present invention, it is possible to proactively control the operating status of the hydroelectric power generation equipment downstream of the hydroelectric power generation intake gate while reliably securing the maintenance flow rate M to the downstream side of the dam.

[0019] The seventh invention is a maintenance flow rate adjustment system comprising a stop weir that holds back water, a water level sensor that detects the level of the water held back by the stop weir, a hydroelectric power generation intake gate that is provided at the stop weir and takes in water to be used in a hydroelectric power generation facility located far from the stop weir, a discharge gate that is provided at the stop weir and discharges water downstream, and a sand flushing gate that is provided at the stop weir and driven by a control mechanism, and in the case where water is taken in from the hydroelectric power generation intake gate and discharged downstream from the discharge gate, the water level L required to ensure the maintenance flow rate M on the downstream side is equal to or greater than water level L. 0When the water level sensor measures the water level L 0 When the discharge volume from the discharge gate falls below , the control mechanism drives the sand discharge gate. 1 and discharge volume from the sand flushing gate F 2 The combined value F of the above is set to be equal to or greater than the maintenance flow rate M. The seventh invention having the above-mentioned configuration is the first invention specified as a product invention, and its action is the same as that of the first invention. Effect of the Invention

[0020] According to the first invention as described above, when the discharge flow rate F downstream from the discharge gate of the dam's water-stopping weir falls below the maintenance flow rate M, the shortfall in the discharge flow rate can be discharged from the sand flushing gate, thereby ensuring the maintenance flow rate M. In this case, there is no need to close the hydroelectric power generation intake gate to ensure the maintenance flow rate M to the downstream side of the dam. Therefore, even if the hydroelectric power generation intake gate cannot operate quickly due to its structure, or if similar symptoms are observed in the hydroelectric power generation intake gate due to aging, etc., the maintenance flow rate M to the downstream side can be ensured without relying on the operation of the hydroelectric power generation intake gate. In addition, in the first invention, even if the hydroelectric power generation water intake gate cannot operate quickly due to its structure, or if the hydroelectric power generation water intake gate shows similar symptoms due to aging, etc., the maintenance flow rate M to the downstream can be easily and quickly secured by opening the sand discharge gate, so there is no need to continue discharging excess water downstream from the discharge gate in preparation for an unexpected sudden drop in the dam water level L. In this case, most of the excess water that is constantly discharged from the discharge gate can be supplied to the hydroelectric power generation facility downstream of the hydroelectric power generation intake gate and used for power generation. As a result, according to the first aspect of the invention, the water in the dam can be effectively used for power generation while ensuring the maintenance flow rate M to the downstream side of the dam. In addition, since there is no need to replace or repair the water intake gate for hydroelectric power generation, the cost of capital investment can be reduced.

[0021] The second invention has the same effect as the first invention. Furthermore, according to the second invention, the discharge flow rate F from the discharge gate and the sand flushing gate to the downstream side of the dam can be made to approach the maintenance flow rate M. In this case, most of the water not used to ensure the maintenance flow rate M can be supplied from the hydroelectric power generation intake gate to the downstream hydroelectric power generation equipment and used for power generation, thereby improving the power generation efficiency of this hydroelectric power generation equipment.

[0022] The third invention has the same effect as the second invention. Furthermore, according to the third invention, the number of times the sand flushing gate is operated, which is necessary to bring the discharge amount F from the discharge gate and the sand flushing gate to the downstream side of the dam closer to the maintenance flow rate M, can be relatively reduced. In this case, the power required to drive the sand flushing gate can be saved.

[0023] The fourth and fifth aspects of the present invention have the same effects as those of the first to third aspects of the present invention. Furthermore, according to the fourth aspect of the present invention, the water level L of the dam is 0 When the water level falls below this level, the sand flushing gate can be driven as quickly as possible to open it as much as desired. As a result, the water level of the dam is L 0 When the river level falls below this level, the possibility that the discharge volume F downstream will fall below the maintenance flow volume M can be minimized. Therefore, according to the fourth and fifth aspects of the present invention, the sand flushing gate can be opened quickly, so that the discharge amount F to the downstream side can be controlled (adjusted) with high accuracy using the sand flushing gate.

[0024] The sixth aspect of the invention has the same effects as the first to fifth aspects of the invention. Furthermore, according to the sixth aspect of the invention, when it becomes difficult to adjust the discharge amount F to the downstream side by opening and closing the sand flushing gate, it is possible to smoothly shift from the control of the sand flushing gate to the control of the water intake gate for hydroelectric power generation. In other words, even in a situation where the closing operation of the hydroelectric power generation water intake gate cannot be performed quickly, by monitoring the opening and closing status of the sand discharge gate, the timing when the closing operation of the hydroelectric power generation water intake gate is necessary can be predicted and the closing operation of the hydroelectric power generation water intake gate can be started. More specifically, when it is confirmed that the opening of the sand flushing gate is gradually increasing and approaching its upper limit, the closing operation of the hydroelectric power generation water intake gate is initiated, thereby allowing the control to ensure the maintenance flow rate M downstream of the dam to be smoothly shifted from control of the sand flushing gate to control of the hydroelectric power generation water intake gate. Therefore, according to the sixth aspect of the present invention, the risk of an emergency shutdown (trip) of the hydroelectric power generation facility downstream of the hydroelectric power generation water intake gate can be reduced, allowing the downstream hydroelectric power generation facility to operate smoothly.

[0025] The seventh invention specifies the above-mentioned first invention as a method invention, and its effects are the same as those of the first invention. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is an image diagram of a maintenance flow rate adjustment system according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a system configuration diagram of a maintenance flow rate adjustment system according to an embodiment of the present invention. [Diagram 3] 4 is a flow chart showing a preparation process in a maintenance flow rate adjustment method according to an embodiment of the present invention. [Figure 4] 4 is a flow chart showing a sand flushing gate opening process and a sand flushing gate closing process in the maintenance flow rate adjustment method according to the embodiment of the present invention. [Diagram 5] 4 is a cross-sectional view showing the state of the sand flushing gate in step S10 of the maintenance flow rate adjustment method according to the embodiment of the present invention. FIG. [Figure 6] 4 is a cross-sectional view showing the state of the sand flushing gate in step S11 of the maintenance flow rate adjustment method according to the embodiment of the present invention. FIG. [Figure 7] 4 is a cross-sectional view showing the state of the sand flushing gate in step S13 of the maintenance flow rate adjustment method according to the embodiment of the present invention. FIG. [Figure 8] 4 is a cross-sectional view showing the state of the sand flushing gate in step S22 or step S26 of the maintenance flow rate adjustment method according to the embodiment of the present invention. FIG. [Figure 9] 4 is a cross-sectional view showing the state of the sand flushing gate in step S22 or step S26 of the maintenance flow rate adjustment method according to the embodiment of the present invention. FIG. [Figure 10] 4 is a cross-sectional view showing the state of the sand flushing gate in step S22 or step S24 of the maintenance flow rate adjustment method according to the embodiment of the present invention. FIG. [Figure 11] 1 is an image diagram for explaining the action and effect of a maintenance flow rate adjustment method according to an embodiment of the present invention. FIG. [Figure 12] 13 is a flow chart showing a sand flushing gate opening process and a sand flushing gate closing process in a maintenance flow rate adjustment method according to a modified example of the present embodiment. [Figure 13] This is an image of a dam. [Figure 14] FIG. 14 is an image of the effluent discharged from the dam shown in FIG. 13. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] A maintenance flow rate adjustment system and a maintenance flow rate adjustment method using the same according to an embodiment of the present invention will be described with reference to FIGS. 1 to 12.

[0028] [1-1: Basic configuration of the present invention] First, an overview of the maintenance flow rate adjustment system according to the present invention will be described with reference to FIGS. 1 and 2. FIG. Fig. 1 is a conceptual diagram of a maintenance flow rate adjustment system according to an embodiment of the present invention. Fig. 2 is a system configuration diagram of the same maintenance flow rate adjustment system. Note that the same parts as those shown in Figs. 13 and 14 above are given the same reference numerals, and explanations of their configurations will be omitted. 1 or 2, the dam 2, which is the maintenance flow rate adjustment system 1 according to this embodiment, comprises a cut-off weir 3 that holds back water, a water level sensor 10 (see FIG. 2) that detects the level of the water held back by the cut-off weir 3, a hydroelectric power generation intake gate 4 that is provided on the cut-off weir 3 and takes in water to be used in a hydroelectric power generation facility 13 located far from the cut-off weir 3, a discharge gate 5 (e.g., a fishway) also provided on the cut-off weir 3 and discharges water downstream 12, and a sand flushing gate 6 also provided on the cut-off weir 3 and driven by a control mechanism 7 (see FIG. 2). The water taken in from the hydroelectric power generation intake gate 4 is supplied to the hydroelectric power generation facility 13 through a water passage 14. In addition, the sand flushing gate 6 in the maintenance flow adjustment system 1 of this embodiment is equipped with two switches for driving its control mechanism 7, for example, a water level gauge float switch 8 and a relay 9 (for both, see Figure 2).

[0029] In the maintenance flow rate adjustment system 1 according to the present embodiment described above, when water is taken in from the hydroelectric power generation intake gate 4 and discharged from the discharge gate 5 to the downstream 12 side of the dam 2, the water level L required to ensure the maintenance flow rate M discharged to this downstream 12 side is water level L 0 (See Figure 5 below.) In the maintenance flow rate adjustment system 1 according to this embodiment, the measurement value of the water level L of the dam 2 by the water level sensor 10 is the water level L 0 When the sand discharge amount falls below 100%, the control mechanism 7 drives and opens the sand discharge gate 6, and the discharge amount F discharged from the discharge gate 5 is 1 and the discharge volume F discharged from the sand discharge gate 6. 2 The total value F is controlled to be equal to or greater than the maintenance flow rate M.

[0030] In the maintenance flow rate adjustment system 1 according to this embodiment, "the hydroelectric power generation facility 13 is located far from the cutoff weir 3" means that the discharge water F after the water taken from the hydroelectric power generation intake gate 4 of the dam 2 shown in FIG. 1 is used for power generation in the hydroelectric power generation facility 13 is discharged. 3However, this means that the hydroelectric facility 13 is located far enough away from the dam 2 that it is not considered part of the maintenance flow M downstream 12 of the dam 2 . In addition, the hydroelectric power generation water intake gate 4 that constitutes the maintenance flow control system 1 in this embodiment is equipped with a series of equipment (not shown) for opening and closing the hydroelectric power generation water intake gate 4 as its water intake volume control mechanism, but in the control in the maintenance flow control system 1 in this embodiment, in principle, the opening degree of the hydroelectric power generation water intake gate 4 is always maintained as desired, and the hydroelectric power generation water intake gate 4 is not opened or closed in response to changes in the water level L of the dam 2. Furthermore, the discharge gate 5 constituting the maintenance flow adjustment system 1 in this embodiment also has a discharge flow control mechanism 11, such as a stopper, but in the control in the maintenance flow adjustment system 1 in this embodiment, the opening degree of the discharge gate 5 (the height of the stopper) is in principle always maintained as desired, and the opening degree of the discharge gate 5 is not adjusted in response to changes in the water level L of the dam 2.

[0031] [1-2: Control method of the present invention] Next, a maintenance flow rate adjustment method using the maintenance flow rate adjustment system according to this embodiment will be described with reference to FIGS. Fig. 3 is a flow chart of the preparation process in the maintenance flow adjustment method according to an embodiment of the present invention. Fig. 4 is a flow chart of the sand flushing gate rotation process and the sand flushing gate closing process in the maintenance flow adjustment method according to an embodiment of the present invention. Figs. 5 to 10 are cross-sectional views showing the state of the sand flushing gate in each step of the maintenance flow adjustment method according to an embodiment of the present invention. Note that the same parts as those shown in Figs. 1 and 2, and Figs. 13 and 14 above are given the same reference numerals, and explanations of their configurations will be omitted. First, the preparation step 16 of the maintenance flow rate adjustment method 15 according to this embodiment will be described with reference to FIG. 3, as well as FIGS. As mentioned above, the water level L of the dam 2 required to secure the maintenance flow rate M to the downstream 12 side of the dam 2 shown in Figure 1 is the water level L 0 (See Figure 5). In addition, in the maintenance flow rate adjustment method 15 according to this embodiment, this water level L 0 Water level L that is ΔL higher than 1 is set as the reference water level for the preparation process 16.

[0032] In the maintenance flow rate adjustment method 15 according to this embodiment, for example, as shown in FIG. 5, when the water level L of the dam 2 is 1 If it exceeds this limit, there is no need to control the maintenance flow rate adjustment system 1 according to this embodiment, that is, to control the opening degree of the sand flushing gate 6. For this reason, as shown in Fig. 3, the water level gauge float switch 8 and the relay 9, which are the switches of the control mechanism 7 of the sand flushing gate 6, are both set to "OFF" (step S10).

[0033] On the other hand, if discharge upstream of the dam 2 stops due to, for example, an emergency shutdown (trip) of another hydroelectric power generation facility attached to another dam (not shown) upstream of the dam 2, the water level L of the dam 2 will start to drop. Note that, since the emergency shutdown (trip) of the other hydroelectric power generation facility attached to the other dam upstream as described above occurs unexpectedly, the drop in the water level L of the dam 2 also occurs unexpectedly. And the water level of Dam 2 is L 1 When the water level reaches L, that is, as shown in FIG. 1 When this is detected (step S11 in FIG. 3), the water level gauge float switch 8, one of the two switches of the control mechanism 7 of the sand flushing gate 6, is turned "ON" (step S12 in FIG. 3).

[0034] After this, the water level L of the dam 2 further drops, and the water level L reaches the water level L on the water level gauge float switch 8 (not shown). 0 When it is detected that the sand discharge gate 6 is in the ON state (see FIG. 7, step S13 in FIG. 3), the relay 9 of the two switches of the control mechanism 7 of the sand discharge gate 6 is turned "ON" (step S14 in FIG. 3).

[0035] Furthermore, from this state, the water level L of the dam 2 drops, and the water level L of the water level gauge float switch 8 becomes water level L 0When it is detected that the load is below this value (step S15 in FIG. 3), the preparation step 16 is terminated and the process proceeds to a sand flushing gate opening step 17 and a sand flushing gate closing step 18 (II) shown in FIG.

[0036] In the sand flushing gate opening step 17 following the above-mentioned preparation step 16(I), the opening degree H of the sand flushing gate 6 is set to its upper limit H L After it is confirmed that the depth has not yet reached the threshold (step S21), the sand discharge gate 6 is opened as desired (for example, by about 1 to several cm) in step S22 (see FIG. 8).

[0037] In addition, when the sand flushing gate 6 is opened as desired (for example, by about 1 to several cm) in step S22, a discharge amount F is discharged from the sand flushing gate 6 to the downstream 12 side of the dam 2. 2 [m 3 / s] of water is discharged (see Figure 8). In other words, from the dam 2 (the maintenance flow rate adjustment system 1 according to this embodiment) shown in FIG. 1 to the downstream 12, the discharge amount F discharged from the discharge gate 5 is 1 [m 3 / s] (see Figure 1), the discharge volume F discharged from the sand discharge gate 6 2 [m 3 / s] (see Figures 1 and 8) will be supplied (discharged). As a result, the discharge volume F from the dam 2 to the downstream side 12 (the discharge volume F from the discharge gate 5) 1 and discharge volume F from sand discharge gate 6 2 The sum of these two values ​​reaches or approaches the maintenance flow rate M. In addition, the discharge volume from discharge gate 5 is F 1 and discharge volume F from sand discharge gate 6 2 This can be determined by installing a flow meter (not shown) at the discharge gate 5 or the sand flushing gate 6, or can be calculated by using the opening degree of the discharge gate 5 or the sand flushing gate 6 and the water level L of the dam 2, etc.

[0038] Even if step S22 is performed, the discharge amount F from the discharge gate 5 is still 1 and discharge volume F from sand discharge gate 6 2If the sum F has not reached the maintenance flow rate M, the previous steps S21 and S22 are repeated until the sum F reaches the maintenance flow rate M (see FIGS. 8 to 10). In other words, the opening degree H of the sand discharge gate 6 is gradually increased to increase the discharge amount F from the sand discharge gate 6. 2 By gradually increasing the discharge rate F from Dam 2, it is possible to reach the maintenance flow rate M. The opening degree H of the sand discharge gate 6 is equal to or lower than the upper limit H L As long as the discharge amount F does not reach the limit, the opening degree H of the sand discharge gate 6 is gradually increased to 2 By increasing the discharge volume F from Dam 2 (discharge volume F from discharge gate 5), 1 and discharge volume F from sand discharge gate 6 2 The process of setting the total flow rate (the sum of the above) to the maintenance flow rate M is the sand flushing gate opening process 17 shown by the dashed line in FIG.

[0039] On the other hand, the discharge volume F (the discharge volume F from discharge gate 5) 1 and discharge volume F from sand discharge gate 6 2 Even though the total value of the above has not reached the maintenance flow rate M, the opening degree H of the sand discharge gate 6 is set to the upper limit H in step S21. L (see FIG. 10), or when the opening degree H reaches the upper limit value H by opening the sand discharge gate 6 once more, L When the flow rate reaches 120 m, the maintenance flow rate M on the downstream 12 side of the dam 2 cannot be secured by controlling the sand flushing gate 6 alone. In this situation, it is necessary to reduce or stop the amount of water intake from the hydroelectric power generation intake gate 4 to ensure the maintenance flow rate M. Therefore, the opening degree H of the sand flushing gate 6 is set to the upper opening degree upper limit H L (see FIG. 10), or when the opening degree H reaches the upper limit value H by opening the sand discharge gate 6 once more, L If it reaches this level, the sand flushing gate 6 is fully closed, an alarm is issued to an operator or manager, and control shifts to the hydroelectric power generation water intake gate 4 (step S24 in FIG. 4).

[0040] As described above, in the maintenance flow rate adjustment method 15 according to this embodiment, the hydroelectric power generation intake gate 4 is not controlled while the sand flushing gate 6 is being controlled. In other words, in the maintenance flow rate adjustment method 15 according to this embodiment, the opening degree of the hydroelectric power generation intake gate 4 is in principle maintained at a desired value. Under these circumstances, the sand discharge gate 6 is opened indefinitely to discharge the amount of sand F 2 If the number of gates is increased, the intake of water from the hydroelectric power generation intake gate 4 may suddenly stop, causing a situation in which the hydroelectric power generation facility 13 is unable to generate power (emergency shutdown). In this case, a problem occurs in which the hydroelectric power generation facility 13 cannot be operated smoothly.

[0041] In order to avoid such a situation, in the maintenance flow rate adjustment method 15 according to this embodiment, the upper limit H L is set in advance, and this upper limit value H L By controlling the opening degree H of the sand discharge gate 6 so as not to exceed the upper limit value H L When the opening degree H reaches the upper limit value H L By configuring the system so that the discharge from the sand discharge gate 6 is stopped when the water level reaches this level (step S24 in Figure 4), the hydroelectric power generation equipment 13 downstream of the hydroelectric power generation intake gate 4 can be operated smoothly.

[0042] More specifically, in the maintenance flow rate adjustment method 15 according to this embodiment, the opening degree H of the sand flushing gate 6 is set to the upper opening degree upper limit H L If the situation is approaching this threshold, it is expected that an alarm will be issued from the maintenance flow control system 1 in the near future, so that the closing operation of the hydroelectric power generation water intake gate 4 can be started in advance or preparations for the closing operation can be made in advance. Therefore, since the maintenance flow rate adjustment method 15 of this embodiment includes step S24, the risk of the hydroelectric power generation equipment 13 downstream of the hydroelectric power generation water intake gate 4 being forced to shut down due to a lack of water supply can be preferably avoided.

[0043] On the other hand, after the previous step S22, the discharge amount F from the discharge gate 51 and discharge volume F from sand discharge gate 6 2 If the combined value F exceeds the maintenance flow rate M (step S23 in FIG. 4), it means that excess water exceeding the maintenance flow rate M is being discharged from the dam 2. In this case, in the next step S25, it is confirmed that the sand discharge gate 6 is not fully closed (see FIG. 4), and then in the next step S26, the sand discharge gate 6 is closed for a desired amount (for example, about 1 to several cm) to reduce the discharge amount F from the sand discharge gate 6. 2 Decrease by as much as desired. Since the maintenance flow rate adjustment method 15 according to this embodiment includes steps S23, S25, and S26, it is possible to preferably prevent water from being discharged from the dam 2 in excess of the maintenance flow rate M. In other words, the maintenance flow rate adjustment method 15 according to this embodiment includes the sand flushing gate closing step 18, so that the discharge flow rate F from the discharge gate 5 is 1 and discharge volume F from sand discharge gate 6 2 The opening degree H of the sand flushing gate 6 can be controlled so that the combined value F approaches the maintenance flow rate M. In this case, as much water as possible that does not constitute the maintenance flow rate M can be supplied from the hydroelectric power generation intake gate 4 to the hydroelectric power generation facility 13. As a result, the power generation output of the hydroelectric power generation facility 13 can be increased compared to a case in which the maintenance flow rate adjustment method 15 according to this embodiment is not implemented.

[0044] In the maintenance flow rate adjustment method 15 according to this embodiment, after the sand flushing gate opening step 17, the discharge flow rate F from the dam 2 (the discharge flow rate F from the discharge gate 5) 1 and discharge volume F from sand discharge gate 6 2 When the discharge from another dam located upstream of Dam 2 is resumed after the combined total of the two dams reaches the maintenance flow rate M, the water level L of Dam 2 recovers rapidly. 0 The water level L, which had been below the water level L, has risen to the water level L 1 It will exceed the limit. In this case, as the water level L rises (recovers), the discharge volume F from the discharge gate 5 to the downstream 12 side increases. 1As a result, in step S23 in FIG. 4, the discharge amount F from the dam 2 (the discharge amount F from the discharge gate 5) 1 and discharge volume F from sand discharge gate 6 2 It is determined that the combined total of these values ​​exceeds the maintenance flow rate M. In this case, steps S25 and S26 in Fig. 4 are repeated until the sand flushing gate 6 is fully closed. More specifically, the sand flushing gate 6 gradually changes from the state shown in Fig. 10 to the state shown in Fig. 7.

[0045] Therefore, in the maintenance flow rate adjustment method 15 according to this embodiment, after the sand flushing gate opening step 17, the discharge flow rate F from the dam 2 (the discharge flow rate F from the discharge gate 5 1 and discharge volume F from sand discharge gate 6 2 When the total value of the discharge flow rate F reaches the maintenance flow rate M, or after the sand flushing gate opening step 17, the water level L of the dam 2 is restored and the discharge flow rate F from the sand flushing gate 6 is increased. 2 When the sand discharge gate 6 is no longer needed, the sand discharge gate closing step 18 is a step of completely closing the sand discharge gate 6.

[0046] The opening degree H of the sand discharge gate 6 is set to the upper limit H L When the opening degree H of the sand discharge gate 6 finally becomes zero again, that is, when the sand discharge gate 6 is fully closed, the sand discharge gate closing process 18 (II) shown in FIG. 4 is terminated and the process proceeds to I shown in FIG. 3. That is, both of the two switches (the water level gauge float switch 8 and the relay 9) of the control mechanism 7 of the sand flushing gate 6 are turned "OFF," and the control of the maintenance flow rate adjustment system 1 according to this embodiment ends.

[0047] In addition, in a state where the control of the maintenance flow rate adjustment system 1 according to this embodiment is terminated, for example, as shown in FIG. 5, when the water level L of the dam 2 is lower than the reference water level L 1 If the water intake amount F from the hydroelectric power generation intake gate 4 is exceeded, the hydroelectric power generation intake gate 4 is opened. 3 Increase the water level L of Dam 2 to the reference water level L 1By approaching this, the power generation output of the hydroelectric power generation facility 13 can be increased.

[0048] [1-3: Actions and Effects of the Present Invention] Here, the action and effect of the maintenance flow rate adjustment method 15 according to this embodiment will be described with reference to FIG. Fig. 11 is an image diagram for explaining the action and effect of the maintenance flow rate adjustment method according to the embodiment of the present invention. Note that the same parts as those shown in Figs. 1 to 10, 13 and 14 are given the same reference numerals, and explanations of their configurations will be omitted. <1-3-1: About the sand discharge gate opening process> The maintenance flow rate adjustment method 15 according to the present embodiment as described above includes a sand flushing gate opening step 17 as shown in FIG. 4, so that the water level L of the dam 2 is 0 When the discharge amount F from the discharge gate 5 falls below 120 mm, the sand discharge gate 6 is opened as desired to discharge water from the sand discharge gate 6 to the downstream 12 side. 1 and discharge volume F from sand discharge gate 6 2 The combined value F can be made equal to or greater than the maintenance flow rate M. As a result, even if the water supply to the dam 2 from the upstream side of the dam 2 suddenly decreases or stops unexpectedly, the maintenance flow rate M to the downstream 12 side of the dam 2 can be quickly secured without any change in the opening degree of the hydroelectric power generation intake gate 4 and the discharge gate 5. Therefore, according to the maintenance flow rate adjustment method 15 of this embodiment, even if, for example, the hydroelectric power generation water intake gate 4 or the discharge gate 5 cannot be opened and closed quickly due to their structure, or if similar symptoms are observed in the hydroelectric power generation water intake gate 4 or the discharge gate 5 due to aging, etc., the maintenance flow rate M to the downstream 12 side of the dam 2 can be secured by using the sand flushing gate 6.

[0049] That is, for example, as shown in FIG. 11, in the case where the maintenance flow rate adjustment method 15 according to this embodiment is not implemented (prior art; see FIG. 14), and the opening degree of the hydroelectric power generation intake gate 4 and the discharge gate 5 cannot be adjusted quickly, the water level L of the dam 2 is set to the water level L so that the maintenance flow rate M to the downstream 12 side can be secured even if an unexpected and sudden drop in the water level L occurs in the dam 2. 0 The operational water level L is much higher than P In this case, the water level of the water stored in Dam 2 must be set to L P and water level L 0 Difference S A In addition to the maintenance flow rate M, the company was forced to release an additional amount of water corresponding to the amount of water discharged downstream 12 (see Figure 14). In contrast, when implementing the maintenance flow rate adjustment method 15 according to this embodiment, the water level L of the dam 2 is set to the water level L 1 A slightly higher operating water level L Q By simply maintaining the flow rate M to the downstream 12 side at this level, the flow rate M can be maintained (see FIG. 11). In this case, the operating water level L P and the operating water level L Q Difference S B The amount of water corresponding to this, that is, the water that would have been discharged in excess downstream 12 in the conventional technology, can be supplied from the hydroelectric power generation intake gate 4 to the hydroelectric power generation facility 13 and used to generate electricity in the hydroelectric power generation facility 13 (see Figure 11). Therefore, according to the maintenance flow rate adjustment method 15 of this embodiment, while ensuring the maintenance flow rate M to the downstream 12 side of the dam 2, as much water as possible that does not constitute the maintenance flow rate M can be sent from the hydroelectric power generation intake gate 4 to the hydroelectric power generation equipment 13 for use in power generation. Furthermore, according to the maintenance flow rate adjustment method 15 of this embodiment, there is no need to replace or renovate the hydroelectric power generation intake gate 4 or discharge gate 5 in order to achieve the above-mentioned effects, so capital investment in the dam 2 (the maintenance flow rate adjustment system 1 of this embodiment) can be reduced.

[0050] <1-3-2: About the sand flushing gate closing process> Furthermore, since the maintenance flow rate adjustment method 15 according to this embodiment includes a sand flushing gate closing step 18 as shown in FIG. 4, when the discharge flow rate F to the downstream 12 side of the dam 2 exceeds the maintenance flow rate M, the opening degree of the sand flushing gate 6 can be narrowed as desired to bring the discharge flow rate F closer to the maintenance flow rate M, or when the discharge flow rate F exceeds the maintenance flow rate M and the water level L of the dam 2 falls below the water level L. 0 When the level of the sand discharge gate 6 has recovered to a position exceeding this level, the discharge from the sand discharge gate 6 to the downstream 12 side can be stopped (ended). In this case, excess water exceeding the maintenance flow rate M is prevented from being discharged to the downstream 12 side of the dam 2, and the stored water can be sent from the hydroelectric power generation intake gate 4 to the hydroelectric power generation equipment 13, allowing it to be used efficiently for power generation.

[0051] On the other hand, the sand flushing gate closing step 18 in the maintenance flow rate adjustment method 15 according to this embodiment is not an essential step. The reason for this is that the main purpose of controlling the opening and closing of the sand discharge gate 6 in the maintenance flow rate adjustment method 15 according to this embodiment is to reduce the discharge flow rate F 1 When the flow rate falls below the maintenance flow rate M, the shortfall is quickly compensated for by the discharge flow rate F from the sand discharge gate 6. 2 The answer is to make up for this. Therefore, as long as the discharge F from the dam 2 meets the maintenance flow rate M, the discharge of excess water exceeding the maintenance flow rate M downstream 12 is not a significant issue compared to the discharge F not meeting the maintenance flow rate M. Therefore, in the maintenance flow rate adjustment method 15 according to this embodiment, the sand flushing gate opening step 17 needs to be performed automatically and quickly, but the sand flushing gate closing step 18 does not have such urgency. Therefore, in the maintenance flow rate adjustment method 15 according to this embodiment, after the sand flushing gate opening step 17 is performed and the discharge flow rate F reaches the maintenance flow rate M, the water level L of the dam 2 is 1 When the level of the sand discharged from the gate 6 is exceeded and the water level is restored, an operator may manually close the gate 6 to stop the discharge from the gate 6. Therefore, the sand flushing gate closing step 18 in the maintenance flow rate adjustment method 15 according to this embodiment is an optional component.

[0052] <1-3-3: Preparation process> Furthermore, when the maintenance flow rate adjustment method 15 according to this embodiment includes a preparation step 16 as shown in FIG. 3, the water level L of the dam 2 is 0 When the water level falls below this level, the sand flushing gate 6 can be opened as quickly as possible. In this case, for example, in the case where the sand flushing gate 6 cannot be operated immediately after the switch of the control mechanism 7 (e.g., the water level gauge float switch 8 or the relay 9) is turned "ON" due to the performance of the control mechanism 7 of the sand flushing gate 6 or the drive mechanism not shown, the time required from turning "ON" to the switch of the control mechanism 7 being turned "ON" until the sand flushing gate 6 actually starts operating can be shortened. In other words, when a shortage of the maintenance flow rate M occurs on the downstream side 12 of the dam 2, the discharge flow rate F from the sand flushing gate 6 to the downstream side 12 is 2 Therefore, the time required for the supply of the liquid can be shortened. In this case, the water level of Dam 2 is L 0 When the discharge flow rate F from the dam 2 falls below the maintenance flow rate M, it is possible to preferably prevent the discharge flow rate F from the dam 2 from unintentionally falling below the maintenance flow rate M.

[0053] In addition, in the maintenance flow rate adjustment method 15 according to this embodiment, the preparation step 16 is not an essential step. The reason for this is that in the maintenance flow rate adjustment method 15 according to this embodiment, the timing for starting the opening operation of the sand flushing gate 6 is set so that the water level L of the dam 2 is equal to or lower than the water level L 0 The timing is set when the water level falls below L (see Figures 3 and 4). 0 By moving the gate forward slightly before the maintenance flow rate M is reached, it is possible to preferably avoid a situation in which the discharge flow rate F from the dam 2 unintentionally falls below the maintenance flow rate M, even if it takes some time from when the switch of the control mechanism 7 is turned "ON" until the sand discharge gate 6 actually operates. Therefore, the preparation step 16 in the maintenance flow rate adjustment method 15 according to this embodiment is also an optional component.

[0054] <1-3-4: Regarding the switch of the control mechanism for the sand discharge gate> The maintenance flow rate adjustment method 15 of this embodiment (maintenance flow rate adjustment system 1 of this embodiment) is provided with two types of switches for the sand flushing gate 6, a water level gauge float switch 8 and a relay 9, so that a preparation process 16 as shown in Figure 3 above can be provided when performing the opening operation of the sand flushing gate 6. In this case, as described above in <1-3-3>, the switch of the control mechanism 7 is turned "ON" and then the sand discharge gate 6 actually operates, and the discharge amount F is discharged from the sand discharge gate 6 to the downstream 12 side. 2 Therefore, the time required for the supply of the liquid can be shortened. In this case, the water level of Dam 2 is L 0 When the discharge flow rate F from the dam 2 falls below the maintenance flow rate M, it is possible to preferably prevent the discharge flow rate F from the dam 2 from unintentionally falling below the maintenance flow rate M.

[0055] On the other hand, the switches of the sand flushing gate 6 in the maintenance flow rate adjustment method 15 according to this embodiment (maintenance flow rate adjustment system 1 according to this embodiment) do not need to be limited to two types, the water level gauge float switch 8 and the relay 9, and other switches having similar functions can be used. In this case, it may be possible to open the sand flushing gate 6 without going through the preparation step 16 shown in FIG. 3. Therefore, it is also an optional component to set the switch of the sand flushing gate 6 in the maintenance flow adjustment method 15 of this embodiment (the maintenance flow adjustment system 1 of this embodiment) to two types: a water level gauge float switch 8 and a relay 9.

[0056] <1-3-5: About step S24> When the maintenance flow rate adjustment method 15 according to this embodiment includes step S24 as shown in FIG. 4, the opening degree H of the sand flush gate 6 in the sand flush gate opening step 17 is set to the upper opening degree upper limit H L It is possible to prevent the opening operation from exceeding the limit. In this case, as described above in <1-2>, it is possible to effectively prevent the hydroelectric power generation equipment 13 downstream of the hydroelectric power generation intake gate 4 from suddenly ceasing water intake (tripping) due to the sudden ceasing of water intake from the hydroelectric power generation intake gate 4. In this case, the operation of the hydroelectric power generation facility 13 can be performed smoothly, so that the power generation efficiency of the hydroelectric power generation facility 13 that utilizes the water stored in the dam 2 can be improved.

[0057] On the other hand, when the opening degree of the sand discharge gate 6 is set to zero in step S24 in the maintenance flow rate adjustment method 15 according to this embodiment, that is, when the sand discharge gate 6 is fully closed, the discharge amount F from the sand discharge gate 6 is 2 becomes zero. In this case, there is a possibility that the maintenance flow rate M from the dam 2 to the downstream 12 side cannot be secured. This condition means that there is not enough water in the dam 2 to operate the hydroelectric plant 13. In such a case, after stopping or restricting the intake of water from the hydroelectric power generation intake gate 4, the sand discharge gate 6 is fully closed and the discharge amount F from the discharge gate 5 is 1 It will be necessary to respond according to the situation, such as ensuring the maintenance flow rate M by only using the Therefore, step S24 in the maintenance flow rate adjustment method 15 according to this embodiment is also not a required component, but an optional component.

[0058] [2-1: Modifications of the present invention] <2-1-1; About the modified example> A modification of the maintenance flow rate adjustment method according to this embodiment (maintenance flow rate adjustment system according to this embodiment) will be described with reference to FIG. Figure 12 shows the flow of the sand flush gate opening process and the sand flush gate closing process in the maintenance flow rate adjustment method according to a modified example of this embodiment. The same parts as those shown in Figures 1 to 11, 13 and 14 are given the same reference numerals, and the explanation of their configurations will be omitted. Also, only the parts that differ from the maintenance flow rate adjustment method 15 according to the previous embodiment will be explained here, and the explanation of the common parts will be omitted. In the maintenance flow rate adjustment method 15 according to the present embodiment, a maintenance flow rate M, which is an arbitrary numerical value without a numerical range, is set as a threshold value for opening (sand flush gate opening step 17) or closing (sand flush gate closing step 18) the sand flush gate 6 as desired. In this case, if the discharge rate F from the dam 2 exceeds the maintenance flow rate M after the sand discharge gate 6 has been opened to the desired extent, and if the discharge rate F falls below the maintenance flow rate M after the sand discharge gate 6 has been opened to the desired extent thereafter, the opening and closing of the sand discharge gate 6 will be repeated alternately to maintain the discharge rate F at the maintenance flow rate M.

[0059] In contrast, in the maintenance flow rate adjustment method 15' according to the modified example of this embodiment, the maintenance flow rate lower limit M is used as a threshold value when the sand discharge gate 6 is opened as desired (sand discharge gate opening step 17'). 1 However, the upper limit of the maintenance flow rate M is set as a threshold value when the sand discharge gate 6 is closed as desired (sand discharge gate closing step 18'). 2 are set respectively. In addition, the lower limit of the maintenance flow rate M 1 and the upper limit of the maintenance flow rate M 2 is the lower limit of the maintenance flow rate M 1 <Maintained flow rate M<Maintained flow rate upper limit M 2 However, in order to more reliably secure the maintenance flow rate M to the downstream 12 side of the dam 2, the maintenance flow rate M<the lower limit value M of the maintenance flow rate 1 <Maintained flow rate upper limit M 2 A numerical value may be set so that

[0060] In this case, in the maintenance flow rate adjustment method 15' according to the modification, for example, as shown in FIG. 12, after the sand flushing gate 6 is opened as desired in step S22 of the sand flushing gate opening process 17', the discharge amount F from the dam 2 (the discharge amount F from the discharge gate 5) is calculated in the subsequent step S23a. 1 and discharge volume F from sand discharge gate 6 2 The total value of the above is the minimum maintenance flow rate M 1 It is confirmed whether the discharge volume F reaches the lower limit of the maintenance flow volume M 1 If the discharge volume F does not reach the lower limit of the maintenance volume M 1 Steps S21 and S22 are repeated in this order until On the other hand, in step S23a shown in FIG. 12, the discharge amount F from the dam 2 is set to the minimum maintenance flow amount M 1If it is determined that the discharge amount F from the dam 2 has reached the upper limit M of the sustained discharge amount, the process proceeds to step S23b in the sand flushing gate closing process 18'. 2 It is checked whether it has been reached. In step S23b, the discharge amount F from the dam 2 is set to the upper limit M 2 If it is determined that the time has not been reached, the process returns to step S23a of the sand flushing gate opening process 17', and the subsequent processes are repeated. On the other hand, in step S23b, the discharge amount F from the dam 2 is set to the maintenance flow upper limit M 2 If it is determined that the discharge volume F has reached the upper limit of the sustained discharge volume M 2 Steps S25 and S26 are repeated in this order until the opening degree of the sand flushing gate 6 reaches zero, that is, when the sand flushing gate 6 is fully closed, the control of the sand flushing gate 6 is terminated and the process proceeds to I shown in FIG. 3, where the switches of the control mechanism 7 of the sand flushing gate 6, such as the water level gauge float switch 8 and the relay 9, are both turned "OFF."

[0061] Therefore, as shown in FIG. 12, in the maintenance flow rate adjustment method 15′ according to the modified embodiment of the present invention, after the sand flushing gate 6 is opened as desired in the sand flushing gate opening step 17′ (after step S22), the discharge flow rate F from the dam 2 is set to the maintenance flow rate lower limit M 1 and the upper limit of the maintenance flow rate M 2 If the gate is between these two, the sand discharge gate 6 will not operate and will be in standby mode.

[0062] <2-1-2; Effects and effects of modified versions> According to the maintenance flow rate adjustment method 15′ according to the modified example of the present embodiment as described above, the maintenance flow rate lower limit M 1 and the upper limit of the maintenance flow rate M 2 By setting this, the number of times the sand flushing gate 6 needs to be operated to set the discharge rate F from the dam 2 to the maintenance flow rate M can be made relatively smaller compared to the case where the maintenance flow rate adjustment method 15 according to the previous embodiment is implemented. In this case, implementing the maintenance flow adjustment method 15' of the modified example is expected to result in a slightly larger discharge flow rate F discharged to the downstream 12 side of the dam 2 than when implementing the maintenance flow adjustment method 15 of this embodiment, but it has another advantage in that it saves the electricity required to operate the sand discharge gate 6.

[0063] [3;Other] The maintenance flow rate adjustment system 1 of this embodiment shown in Figures 1 and 2 is a product invention that specifies the group of components necessary to implement the maintenance flow rate adjustment method 15 of this embodiment shown in Figures 3 and 4. Therefore, the actions and effects of the maintenance flow rate adjustment system 1 according to this embodiment are the same as the actions and effects of the maintenance flow rate adjustment method 15 according to this embodiment. [Industrial Applicability]

[0064] As described above, the present invention provides a maintenance flow rate adjustment method and maintenance flow rate adjustment system that can increase the amount of water taken in for hydroelectric power generation while ensuring the maintenance flow rate when taking water from a dam through a hydroelectric power generation intake gate and discharging the maintenance flow rate downstream of the dam from a discharge gate, and can be used in technical fields related to hydroelectric power generation facilities and flood control. [Explanation of symbols]

[0065] 1...Maintenance flow rate adjustment system 2...Dam 3...Stop-water weir 4...Hydroelectric power generation water intake gate 5...Discharge gate (fishway) 6...Sand flushing gate 7...Control mechanism 8...Water level gauge float switch 9...Relay 10...Water level sensor 11...Discharge rate control mechanism (e.g., drop gate) 12, 12'...Downstream 13...Hydroelectric power generation equipment 14...Waterway 15, 15'...Maintenance flow rate adjustment method 16...Preparation process 17, 17'...Sand flushing gate opening process 18, 18'...Sand flushing gate closing process 50...Dam

Claims

1. A dam comprising a cut-off weir that holds back water, a hydroelectric power generation intake gate that is provided at the cut-off weir and takes in water to be used in a hydroelectric power generation facility located far from the cut-off weir, a discharge gate that is provided at the cut-off weir and discharges water downstream, and a sand flushing gate that is provided at the cut-off weir, When water is taken from the hydroelectric power generation intake gate and discharged to the downstream side from the discharge gate, the water level L of the dam required to ensure a maintenance flow rate M on the downstream side is equal to or greater than the water level L. ０ If The water level L is the water level L ０ When the discharge amount from the discharge gate falls below １ and the discharge volume F from the sand discharge gate ２ a sand flushing gate opening step of gradually increasing the opening degree of the sand flushing gate until the sum F of the above-mentioned flow rates reaches the maintained flow rate M.

2. When the total value F exceeds the maintenance flow rate M, 2. The method for adjusting the maintenance flow rate according to claim 1, further comprising a step of closing the sand flushing gate by gradually decreasing the opening of the sand flushing gate until the combined value F reaches the maintenance flow rate M.

3. The maintenance flow rate M is a lower limit value M １ and the upper limit of the maintenance flow rate M ２ It consists of: The total value F is the maintenance flow rate lower limit M １ and the maintained flow rate upper limit M ２ 3. The method for adjusting the maintenance flow rate according to claim 2, wherein the sand flushing gate is not operated when the flow rate is equal to or lower than the predetermined value.

4. Said water level L ０ Water level L higher by ΔL １ is set, The water level L of the dam is １ The method for adjusting the maintenance flow rate according to any one of claims 1 to 3, further comprising a preparation step of turning on a switch of a control mechanism that drives the sand flushing gate when the flow rate reaches the predetermined value.

5. The switch is Water level gauge float switch, A relay; The water level L of the dam is １ When the water level of the dam reaches the water level L, the water level gauge float switch is turned on. ０ 5. The method for adjusting the maintenance flow rate according to claim 4, further comprising the step of turning on the relay and opening the sand flushing gate when the current flow rate falls below the threshold voltage.

6. The upper limit H of the opening degree H of the sand discharge gate Ｌ is set, In the sand discharge gate opening step, the opening degree H of the sand discharge gate is set to the upper limit value H Ｌ 6. The method for adjusting the maintenance flow rate according to claim 1, further comprising the step of: issuing an alarm and fully closing the sand flushing gate when the flow rate exceeds or has exceeded the limit of the predetermined limit.

7. A water stop dam that holds back water, a water level sensor that detects the level of water blocked by the water cutoff dam; a hydroelectric power generation water intake gate that is provided at the cutoff weir and takes in water to be used in a hydroelectric power generation facility located far from the cutoff weir; a discharge gate provided in the water cutoff dam and discharging water downstream thereof; a sand flushing gate provided in the water cutoff dam and driven by a control mechanism; When water is taken from the hydroelectric power generation intake gate and discharged to the downstream side from the discharge gate, the water level L required to ensure the maintenance flow rate M on the downstream side is equal to or greater than the water level L. ０ If The measurement value by the water level sensor is the water level L ０ When the discharge amount F from the discharge gate is less than the threshold value, the control mechanism drives the sand discharge gate. １ and the discharge volume F from the sand discharge gate ２ The maintenance flow rate adjustment system is characterized in that the total value F of the above is set to be equal to or greater than the maintenance flow rate M.

Images