JP2010248842A - Predicting method, predicting system and predicting program for inflow sediment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine a time point for water intake stop, and to restart in order to obtain maximum generated electric energy while restraining a large amount of a sediment inflow when water is discharged in a run-off river-type hydroelectric power station. <P>SOLUTION: The following three processes are executed: a first process where rainfall data in an upper river basin are inputted into a first model formula, and a river water volume and a conveyed sediment volume in the vicinity of an water intake gate after predetermined hours are calculated; a second process where values of the river water volume and conveyed sediment volume which are calculated by the first model formula, and an existing accumulated sediment volume are inputted into a second model formula, and an accumulated sediment volume in front of the water intake gate and a sediment inflow volume into the water intake gate after predetermined hours are calculated; and a third process where a comparison is made between the sediment inflow volume into the water intake gate and a predetermined limiting value, so that a time point at which the sediment inflow volume reaches the limiting value is specified as timing for stopping intake of the water. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an inflow sediment prediction method, an inflow sediment prediction system, and an inflow sediment prediction program. Specifically, in an inflow hydropower plant, the largest inflow of sediment during a flood is suppressed. The present invention relates to a technique for determining the timing of stopping / resuming water intake for obtaining generated power.

  In the flow-type hydroelectric power plant, the river water flow is led from the intake to the water conduit for power generation. Since the river flow contains earth and sand, sediment accumulation tends to occur around water intake facilities such as water intakes, water intake dams, and drainage gates. In view of this, there have been proposed a device for detecting earth and sand in a waterway of such a flow-type hydroelectric power plant, a technique relating to a method for operating a sand discharge gate, and the like.

  For example, an inflow sediment detection device for detecting sediment flowing into a water conduit of a hydroelectric power plant, and an acceleration signal generated in the structure when the sand collides with a structure installed in the water conduit And an acceleration detecting means for detecting the calculation of the sediment inflow frequency and the amount of inflow from at least the presence / absence of inflow sediment and the number of sediment particles flowing in per unit time by processing the acceleration signal detected by the acceleration detection means. An inflow sediment detection device (see Patent Document 1) and the like provided are proposed.

  In addition, a historical analysis process to acquire sediment sediment volume data for each drainage gate operation pattern with respect to downstream water level fluctuations in each water discharge pattern, and a drainage gate where the sediment level is minimized when the downstream water level fluctuation is below a predetermined standard. Corresponding table creation process for creating the correspondence table between the flooding pattern and the drainage gate optimum operation pattern by specifying the optimum operation pattern for each flooding pattern, and matching the flooding information at the time of actual flooding with the corresponding table according to the flooding pattern A drainage gate operation method (refer to Patent Document 2) for performing an optimum pattern specifying step of identifying a drainage gate optimum operation pattern and executing a drainage gate operation process based on the drainage gate optimum operation pattern Proposed.

Japanese Patent Laid-Open No. 10-68118 JP 2008-174969 A

By the way, in an inflow type hydroelectric power station, if water intake is continued at the time of large water discharge, a large amount of earth and sand may flow from the water intake toward the water conduit. In order to prevent such inflow of sediment, water intake may be stopped at the time of water discharge, but the judgment criteria at that time are not established, and if the operation stop is too early and the power generation amount decreases, or the operation stop is too late, May flow in large quantities.
Accordingly, the present invention has been made in view of the above-mentioned problems, and determines the timing of stopping / resuming intake, which obtains the maximum amount of generated electric power while suppressing a large amount of sediment inflow at the time of flooding in the inflow type hydroelectric power plant. The main purpose is to provide technology.

  The inflow sediment prediction method of the present invention that solves the above problems is a prediction method for the amount of inflow sediment in a flow-in hydroelectric power plant, and includes the following steps. That is, for rainfall in the upstream area of the intake river, the first model formula that calculates the river water volume near the intake and the transported sediment from the upstream after a predetermined time is used to calculate the rainfall at the rainfall station in the upstream area at the predetermined time. First step of inputting data and calculating the amount of river water and transported sediment near the intake after a predetermined time from the predetermined time, and the amount of river water, transported sediment and intake near the intake at the predetermined time The amount of river water calculated by the above-mentioned first model equation to the second model equation for calculating the amount of sediment deposited before the intake after a predetermined time and the amount of sediment flowing into the intake after the predetermined time, The second step of calculating the amount of sediment transported and the amount of existing sediment, calculating the amount of sediment deposited before the intake and the amount of sediment flowing into the intake after the predetermined time, and the inflow of sediment into the intake The quantity and the predetermined limit And compare the time when the sediment inflow reaches the limit value is a third step of specifying the intake stop timing.

  In each of the first to third steps, a computer program for realizing this is a scale that can be easily operated on a general personal computer or the like, and executes a numerical analysis model over several tens of hours as in the past. Such trouble and expense are not required. Therefore, the process of acquiring the rainfall data in the upstream area and applying it to the first process, applying the result of the first process to the second process, and further executing the third process is performed in the upstream area. Can be executed as soon as the rainfall data is obtained, and it is possible to detect in advance a situation in which a large amount of sediment inflow occurs at the time of flooding and to suppress this. This leads to continuing the water intake as much as possible until a large amount of sediment flows into the water intake, which in turn leads to the maximization of the amount of power generated at the flow-in hydroelectric power plant.

  In the third step, it is preferable to perform a water intake stop process of the flow-in hydropower station in accordance with the water intake stop timing. This water intake stop process can be executed by giving an instruction to the water intake opening / closing device to close the water intake opening. Alternatively, the inflow sediment prediction system (computer) can be executed by giving an instruction to close the intake port to the intake port opening / closing device (connected to the inflow sediment prediction system).

  In addition, after the intake stop process, the first step and the second step are continuously executed, and the amount of earth and sand flowing into the water intake at a certain point is compared with a predetermined reference value. It is also preferable to execute the fourth step of specifying the time point below the reference value as the water resumption timing. According to this, it is possible not only to simply stop the water intake but also to specify the timing of resuming the water intake, which leads to the maximization of the amount of power generated at the flow-in hydroelectric power station. In addition, in the said 4th process, it is suitable if the intake resumption process of a flow-in type hydropower station is performed according to the said intake resumption timing. This water intake resumption process can be executed by giving an instruction to the water intake opening and closing device to open the water intake. Alternatively, the inflow sediment prediction system (computer) can be executed by giving an instruction to open the intake port to the intake opening and closing device (connected to the inflow sediment prediction system).

  Moreover, the inflow sediment prediction system of the present invention is a computer system that predicts the amount of inflow sediment in a flow-in hydroelectric power plant, and for example, a server device that manages the flow-in hydropower plant can be assumed. This inflow sediment prediction system is naturally a computer, but includes a storage device and a computing device.

  This inflow sediment prediction system is based on the first model formula that calculates the amount of river water in the vicinity of the intake after a specified time and the amount of transported sediment from the upstream, and the vicinity of the intake at the specified time for rainfall in the upstream area of the intake river. The second model formula to calculate the sediment accumulation amount before the intake and the sediment inflow to the intake after a predetermined time with respect to the river water volume, the transported sediment volume, and the existing sediment accumulation amount before the intake Is provided.

  In addition, the inflow sediment prediction system obtains the rainfall data of the rainfall observation station in the upstream area at a predetermined time with an input interface, applies the rainfall data to the first model equation read from the storage device, and the predetermined time The first step of calculating the river water amount and the transported sediment amount in the vicinity of the water intake after a predetermined time from the first time, and the values of the river water amount, the transported sediment amount and the existing sediment accumulation amount calculated in the first step are stored in the storage device. Applied to the second model equation read out from the second model equation, a second step of calculating the amount of sediment deposited before the intake and the amount of sediment flowing into the intake after the predetermined time, and the amount of sediment flowing into the intake and a predetermined amount And a third unit that compares a limit value and specifies a time point at which the sediment inflow amount reaches the limit value as a water stop timing.

  In addition, the inflow sediment prediction program of the present invention includes a first model formula for calculating the amount of river water in the vicinity of the intake after a predetermined time and the amount of transport sediment from the upstream for rainfall in the upstream area of the intake river, and a predetermined time. Calculate the amount of sediment deposited before the intake and the amount of sediment flowing into the intake after a specified time against the values of river water, transported sediment, and existing sediment accumulation before the intake. This is a program that includes a storage device that stores two model equations and a calculation device, and causes a computer that predicts the amount of inflow sediment in a flow-in hydroelectric power plant to execute the following steps.

  That is, the step is to input the rainfall data of the rainfall observation station in the upstream area at a predetermined time into the first model formula, and calculate the river water amount and the transported sediment amount near the intake after a predetermined time from the predetermined time. In the first step of calculation, and the second model formula, the values of the river water volume, the transported sediment volume and the existing sediment accumulation volume calculated by the first model formula are input, and the sediment before the intake after the predetermined time. The second step of calculating the amount of sediment and the amount of sediment flowing into the intake port is compared with the amount of sediment flowing into the intake port and a predetermined limit value, and water is taken when the sediment flow rate reaches the limit value. A third step is specified as the stop timing.

  ADVANTAGE OF THE INVENTION According to this invention, in a flow-in type hydroelectric power station, the timing of a water intake stop and restart which can obtain the largest electric power generation amount can be determined, suppressing the large inflow of earth and sand at the time of a flood.

It is a figure which shows the network structure of the inflow sediment prediction system of this embodiment. It is a figure which shows the example of a process sequence of the inflow sediment prediction method in this embodiment. It is a figure which shows the outflow prediction method (tank model) of the water of the upstream area model in this embodiment. It is a figure which shows the coefficient determination example of the tank model in this embodiment. It is a figure which shows the relationship between the flow volume near the power plant by the numerical analysis in this embodiment, and the total amount of sand flow. It is a figure which shows the runoff prediction calculation example of the water and earth and sand by the upstream area model in this embodiment. It is a figure which shows the schematic diagram (about distribution of upstream inflow sediment) of the water intake periphery model in this embodiment. It is a figure which shows the planar two-dimensional numerical-analysis result (time change of a riverbed height) targeting the periphery of the water intake in this embodiment. It is a figure which shows the time change (numerical analysis result) of (phi) in, (phi) out, and (phi) dp in this embodiment. It is a figure which shows the relationship between (phi) in, (phi) out, (phi) dp in this embodiment, and the amount of sediment accumulation sediment in front of a water intake. It is a figure which shows the relationship between (phi) in and (phi) dp in this embodiment, and the amount of total sedimentation sediment in front of a water intake. It is a figure which shows the relationship between the sediment inflow amount after intake resumption, and the front total sedimentation sediment amount. It is a figure which shows the example of the prediction sheet | seat which combined the upstream area model and the water intake vicinity model in this embodiment. It is a figure which shows the numerical formula group 1 used for the numerical analysis model in this embodiment. It is a figure which shows the numerical formula group 2 used for the numerical analysis model in this embodiment. It is a figure which shows the example of a calculation result of the numerical analysis model (upstream area) in this embodiment. It is a figure which shows the numerical formula group 3 used for the numerical analysis model in this embodiment. It is a figure which shows the numerical formula group 4 used for the numerical analysis model in this embodiment. It is a figure which shows the calculation result of the flow and river bed fluctuation | variation around the hydroelectric power plant intake in this embodiment, and inflow sediment.

--- Inflow sediment prediction system ---
Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a network configuration diagram including the inflow sediment prediction system 100 of the present embodiment. In the description of the inflow sediment prediction system 100 here, it is described that the inflow sediment prediction system 100 executes the inflow sediment prediction method of the present invention. However, the inflow sediment prediction method (corresponding to claim 1 and the like) as a construction method is naturally included as a concept.

  In the present embodiment, as shown in the figure, the actual flow-in hydroelectric power plant 5 has a water intake 6 for taking water for power generation and a part for storing a part of the river flow and taking it into the water intake 6. A water intake dam 7 is installed. Further, near the intake dam 7, a sand discharge gate 9 is installed for appropriately discharging the sediment 8 that flows down on the water flow and accumulates in front of the intake 6 and the intake dam 7. Further, a rain gauge 200 for measuring the rainfall in the upstream area is installed on the upstream side of the intake dam 7. The rain gauge 200 is connected to the inflow sediment prediction system 100 via the network 160 or a communication device of the inflow sediment prediction system 100 (NIC 107 described later), and provides the rainfall measurement value upstream of the intake dam to the system side. To do.

  On the other hand, the inflow sediment prediction system 100 (hereinafter, system 100) is a computer system for predicting the amount of inflow sediment in the flow-in hydroelectric power plant 5, and is a hard disk drive for executing the inflow sediment prediction method of the present invention. A program 102 stored in a storage device such as 101 is read into a RAM 103 (memory) and executed by a CPU 104 which is an arithmetic device.

  In addition, the system 100 includes a network interface (NIC) (Network Interface) that handles data exchange with an input interface 105 such as various keyboards and buttons generally provided in a computer device, an output interface 106 such as a display, and a rain gauge 200. Card) or the like.

  The system 100 is connected to the rain gauge 200 via the various networks 160 such as the Internet and a LAN by the NIC 107, and executes data exchange. The system 100 also includes a flash ROM 108, a bridge 109 that relays a bus connecting each unit, and a power source 121. The flash ROM 108 stores a BIOS 120. After the power supply 121 is turned on, the CPU 104 first accesses the flash ROM 108 and executes the BIOS 120 to recognize the system configuration of the system 100. The hard disk drive 101 stores an OS 118 in addition to the functional units and databases. The OS 118 is a program for the CPU 104 to control each unit 101 to 108 of the system 100 and execute each function unit to be described later. In accordance with the BIOS 120, the CPU 104 loads the OS 118 from the hard disk drive 101 to the RAM 103 and executes it. Thereby, the CPU 104 controls each part of the system 100 in an integrated manner.

  Subsequently, functional units (means) configured and held by the system 100 based on the program 102 will be described. It is assumed that the system 100 has a model database 125 that stores the first model formula and the second model formula in an appropriate storage device such as the hard disk drive 101. The model database 125 is a database that stores the first model formula and the second model formula. For example, the model database 125 is a collection of records in which a model name and formula data are associated with a formula ID.

  The system 100 acquires the rainfall data of the rainfall observation station in the upstream area at a predetermined time by the input interface 105 (or acquires from the rain gauge 200 via the communication device 107), and the rain data is stored from the storage device 101. Applying to the read first model formula, the first means 110 for calculating the amount of river water and the amount of transported sediment in the vicinity of the intake after a predetermined time from the predetermined time is provided (corresponding to the first step).

  Further, the system 100 applies the values of the river water amount, the transported sediment amount, and the existing sediment accumulation amount calculated by the first means 110 to the second model formula read from the storage device 101, and after the predetermined time. Is provided with a second means 111 for calculating the amount of sediment deposited before the intake and the amount of sediment flowing into the intake (corresponding to the second step).

  Further, the system 100 compares the amount of sediment flowing into the intake with a predetermined limit value (stored in the storage means 101 in advance), and takes the time when the amount of sediment flowing in reaches the limit value as the water stop timing. The third means 112 for specifying is provided (corresponding to the third step).

  In addition, it is suitable if the said 3rd means 112 performs the water intake stop process of the inflow type hydroelectric power station 5 according to the said water intake stop timing. In this water intake stop process, the input interface 105 receives a water intake closing instruction for the water intake opening / closing device by an attendant, and the water intake opening / closing device (communicatively connected to the system 100) is connected to the water intake opening / closing device. This can be done by giving a close instruction.

  In addition, the system 100 continuously executes the processing by the first means 110 and the second means 111 after the water intake stop processing, and the amount of sediment flowing into the water intake at a certain point in time and a predetermined reference value ( It is preferable to include a fourth means 113 for comparing the time when the sediment inflow amount falls below the reference value as the water resumption timing (corresponding to the fourth step). In addition, it is suitable if the said 4th means 113 performs the water intake restart process of the inflow type hydroelectric power station 5 according to the said water intake restart timing. In this intake resumption process, an intake opening instruction to the intake opening / closing device by the staff is received by the input interface 105, and the intake opening is connected to the intake opening / closing device (communicatively connected to the system 100). This can be done by giving an opening instruction.

  Each of the functional units 110 to 113 in the system 100 shown so far may be realized as a program stored in an appropriate storage device such as a memory such as a RAM or an HDD (Hard Disk Drive), or may be realized as hardware. You may do that. When each functional unit is realized as a program, the CPU 104 reads the corresponding program from the storage device 101 to the RAM 103 and executes it in accordance with the program execution.

  Alternatively, in order to provide measurement data from the rain gauge 200 to the system 100, an operator inputs the measurement data through the input interface 105 of the system 100 based on the measurement data output from the rain gauge 200. Thereby, the system 100 may acquire the measurement data.

--- Main flow of inflow sediment prediction method ---
Hereinafter, the actual procedure of the inflow sediment prediction method in the present embodiment will be described with reference to the drawings. FIG. 2 is a diagram illustrating an example of a processing procedure of the inflow sediment prediction method in the present embodiment. In the case of this example, the various steps corresponding to the inflow sediment prediction method are executed by realizing the first to fourth means by a program that the system 100 reads into the RAM 103 and executes. The program is composed of codes for performing various operations described below.

  First, the first means 110 of the system 100 acquires the rainfall data of the rainfall observation station in the upstream area at a predetermined time with the input interface 105 (or acquired from the rain gauge 200 via the communication device 107) (s100). . Further, the first means 110 applies the rainfall data to the first model equation read from the storage device 101, and the river water amount and the transport sediment in the vicinity of the intake after a predetermined time (Δt) from the predetermined time. Calculate the quantity. Regarding the calculation of the river flow rate in the calculation process by the first means 110, for example, a river flow rate prediction after Δt time is executed by a tank model (details will be described later) (s101). In addition, regarding the calculation of the amount of transported sediment in the calculation process by the first means 110, for example, prediction of the total amount of sand at the intake point after Δt time by Expression 3 described later is executed (s102).

  Further, the second means 111 of the system 100 includes a network 160 from a river water amount and a transported sediment amount calculated by the first means 110 and a value of an existing sediment accumulation amount (a sediment accumulation amount monitoring device installed around a water intake. Or acquired by data input from a staff member located around the intake port) is applied to the second model equation read from the storage device 101, and before the intake port after the predetermined time (Δt). Calculate the amount of sediment and the amount of sediment flowing into the intake. In the calculation processing by the second means 111, for example, φin is calculated from the accumulated sediment volume in front of the current intake port using Equation 5 described later (s103), and the current accumulated sediment inflow volume until Δt time later. The amount of sediment inflow into the water intake after Δt time is calculated (s104). In addition, the sediment that flows into the river channel in front of the intake (total amount of sand that includes the drifting sand and floating sand) is divided into sediment that flows into the intake, sediment that accumulates in front of the intake, and sediment that flows downstream of the dam. Therefore, the ratio of the inflow sediment distributed to these three is defined as φin, φdp, and φout in Equation 4. Therefore, φin indicates the ratio of the sediment flowing into the intake port out of the sediment flowing into the river channel in front of the intake port (the total amount of sediment flowing from the combined sediment and floating sand).

  The third means 112 of the system 100 compares the amount of sediment flowing into the intake 6 calculated up to step s104 with the intake stop reference inflow amount (a predetermined limit value stored in advance in the storage means 101). (S105). If the sediment inflow amount reaches the intake stop reference inflow amount by this comparison processing (s105: YES), the third means 112 identifies this point as the water stop timing. And the said 3rd means 112 gives the instruction | indication which closes a water intake to the opening-and-closing apparatus of the water intake 6 (it connects so that communication is possible via the said system 100 and the said network 160) according to the said water intake stop timing, Water intake stop processing for the flow-in hydroelectric power plant 5 is performed (s106).

  Moreover, the 4th means 113 of the said system 100 continues and performs the process by the said 1st means 110 and the 2nd means 111 after the water intake stop process of the said step s106. In this case, the fourth means 113 calculates φdp by using Equation 6 from the current accumulated sediment amount in front of the intake port (s107). The φdp is the ratio of sediment deposited on the front of the water intake in the sediment flowing into the river channel in front of the water intake (the total amount of sand that flows from the drifting sand and floating sand). Further, the fourth means 113 having calculated φdp adds the accumulated sediment amount up to Δt time to the current accumulated sediment amount in front of the intake port, and calculates the accumulated sediment amount in front of the intake port after Δt time (s108). ). Thereafter, the fourth means 113 repeatedly executes steps s107 and s108 until the end of the water discharge (s109: NO). With regard to the timing of the end of water discharge, for example, the time when the administrator inputs a water discharge end instruction through the input interface 105 and the system 100 receives the instruction, or the rain gauge 200 or the like via the communication device 107 is used. It may be the timing when the water discharge end instruction is acquired from an appropriate monitoring device.

  Thereafter, when the fourth means 113 detects the end of the water discharge (s109: YES), the current intake front accumulated sediment volume (calculated up to step s108) is used, and after resuming the water intake using Equation 8 described later. The amount of earth and sand inflow is predicted (s110). The fourth means 113 compares the amount of earth and sand flowing into the water intake at a certain time point (= a predetermined time after resumption of water intake) with the amount of sediment removal reference inflow (a predetermined reference value stored in advance in the storage means 101). (S111).

  Here, if the sediment inflow amount falls below the sediment removal reference inflow amount (s111: NO), the fourth means 113 identifies this time as the water resumption timing. And the said 4th means 113 gives the instruction | indication which opens an intake port with respect to the opening / closing apparatus of the intake port 6 (it connects so that communication is possible with the said system 100 and the said network 160) according to the said intake resumption timing, The water intake resumption process of the flow-type hydroelectric power plant 5 is performed. That is, the flow-in hydroelectric power plant 5 returns from the intake stop state and resumes normal power generation. Further, the fourth means 113 stores the current sediment inflow amount and the accumulated sediment amount in front of the intake port in the storage means 101 for the next water discharge (s116), and ends the processing.

  On the other hand, in the comparison process in step s111, if the sediment inflow exceeds the sediment removal reference inflow (s111: YES), the fourth means 113, for example, The removal instruction is displayed on the output interface 106, or the sediment removal instruction is transmitted to a terminal such as an administrator via the NIC 107 (s112). Then, the current amount of sediment inflow and the amount of accumulated sediment in front of the intake port are stored in the storage means 101 for the next water discharge (s116), and the process ends.

  On the other hand, if the sediment inflow amount does not reach the intake stop reference inflow amount in the comparison process in step s105 (s105: NO), the fourth means 113 calculates the current accumulated sediment amount in front of the intake port. Φdp is calculated using Equation 6 (s113). φdp, that is, the proportion of sediment deposited in front of the intake of the sediment flowing into the river channel in front of the intake (total amount of sand flow including the drifting sand and floating sand) is calculated. Further, the fourth means 113 adds the accumulated sediment amount until Δt time to the current accumulated sediment amount in front of the intake port, and calculates the accumulated sediment amount in front of the intake port after Δt time (s114). Thereafter, the fourth means 113 returns the process to s100 until the end of the water discharge (s115: NO). Thereafter, when the fourth means 113 detects the end of the water discharge (s115: YES), the current sediment inflow amount and the accumulated sediment amount in front of the intake port are stored in the storage means 101 for the next water discharge (s116) and processed. Exit.

--- About the first model (upstream model) ---
Next, the first model formula used by the first means 110 will be described in detail. The first model formula is a formula group derived by assuming a model called an upstream region model in the upstream region of the river. This upstream model is a tank model as shown in FIG. 3 and reproduces the basin by a tank arranged in several stages vertically (in the example shown in FIG. 3, it is a three-stage tank model, but a four-stage tank). Model). Normally, in this three-stage tank model, the upper tank is associated with surface outflow, the middle stage is associated with intermediate outflow, and the lower stage is associated with groundwater outflow, and outflow from the outflow holes on the side of each tank represents outflow to the river (tank Outflow from the bottom permeation hole indicates penetration into the lower aquifer). That is, the total water Q flowing out from the side outflow holes is the value of the outflow amount (= river water amount).

When this tank model is adopted as the upstream area model, the amount of water outflow from the upstream area of the river is calculated based on the equations shown in FIG. Storage). Here, when the tank heights Ha (t), Hb (t), and Hc (t) at a certain time t are obtained, the tank height Ha (t + Δt) after Δt time (for example, 1 hour later) , Hb (t + Δt) and Hc (t + Δt) are obtained by the following three formulas (collectively, these are stored in the model database 125 as the first model formula).
Ha (t + Δt) = Ha (t) + r (t) − (Q1 + Q2 + qa)
Hb (t + Δt) = Hb (t) − (Q3 + qb)
Hc (t + Δt) = Hc (t) −Q4

Further, from the Ha (t + Δt), Hb (t + Δt), and Hc (t + Δt) obtained by the above formula 1, the following five formulas (collectively, formula 2: the model database 125 as the first model formula: To store the amount of outflow after Δt time.
Q1 (t + Δt) = α1 × (Ha (t + Δt) −Z1)
Q2 (t + Δt) = α2 × (Ha (t + Δt) −Z2)
Q3 (t + Δt) = α3 × (Hb (t + Δt) −Z3)
Q4 (t + Δt) = α4 × Hc (t + Δt)
Q (t + Δt) = (Q1 (t + Δt) + Q2 (t + Δt) + Q3 (t + Δt + Q4 (t + Δt)) × Ab /3.6

  By the above calculation, the amount of runoff after Δt time can be calculated by inputting the rainfall at the current time. By repeating this calculation every time, for example, the flow rate Q in the vicinity of the power plant intake after Δt time can be predicted from the rainfall that changes during the flood period.

  In addition, α1, α2, α3, α4, β1, and β2 in each equation are coefficients and have different values for each basin, and therefore need to be set for each target power plant basin. Here, the identification may be made from the known rainfall and the measured record of the amount of water discharge (= river water amount). For example, when there is rainfall time series data and river water volume record for a certain flood, the river flow of the calculation result and the actual river water volume record when the above variables α1, α2, α3, α4, β1, β2 are given temporarily And compare. The calculation is repeated for various α1, α2, α3, α4, β1, and β2, and the coefficient value with the smallest difference between the calculation result and the actual measurement result is adopted.

  For example, on the basis of the rainfall record and water discharge record of a certain power plant, when the calculation result and the actual measurement result are compared with the combination of the coefficients shown in Table 1 shown in FIG. 4 (patterns A to C), the graph g4 in the lower part of FIG. became. From this graph g4, it can be determined that the coefficient pattern having the best compatibility with the actually measured value is “coefficient pattern B”. In practice, numerical calculation is performed by a computer using a large number of coefficient patterns from a large amount of flood data, and a coefficient pattern having the smallest average error (difference between measured value and calculated value) is adopted.

  By inputting the rainfall amount at the current time in the above-described calculation using the tank model, it is possible to predict the river water amount in the vicinity of the water intake at Δt (for example, one hour after the current time). In the explanation of this part, the explanation was made using an example of a normal three-stage tank model. However, Nagai et al. -64, 1995.) A tank model with long and short term combination may be used. When this long and short-term tank model is used, it is possible to predict the amount of river water near the intake with higher accuracy by inputting daily rainfall during normal times and inputting hourly rainfall during flooding.

Next, a description will be given of the prediction of the amount of transported sediment (amount of swept sand and the amount of suspended sand) by the upstream model. Based on the amount of river water predicted by the tank model described above, the amount of suspended and swept sand transported from the upstream area to the vicinity of the intake is predicted. In this model, the total amount of sand flow, which is the sum of the amount of suspended sand and the amount of suspended sand, is estimated by the following equation (3).
VTL = α × (Q) 2 Equation 3
Here, VTL: Total sand flow (m ³ / s) carried near the power plant intake. Here, α is a coefficient that is different for each basin and needs to be set for each target power plant basin. However, it is very difficult to actually measure the total amount of sand, which is the sum of the suspended sand and the amount of suspended sand. In that case, the coefficient cannot be identified by an actual measurement value as in the tank model described above.

  Therefore, a numerical analysis model (one-dimensional analysis) that can reproduce the river network and sediment runoff in the upstream area is separately performed, and the coefficient α is determined using the result. This numerical analysis model reproduces the flow of water and sediment from the mountain slope in the upstream area and the process of flowing water and sediment flowing through the river to the vicinity of the power plant intake, with 10-minute rainfall as an input condition. is there. The accuracy of this model has been confirmed by comparing the past water discharge and the amount of sediment flowing into the power plant.

  However, this numerical analysis model cannot be used for prediction at the time of actual flooding because the calculation time is as long as several hours to several tens of hours even in a standard watershed (about the formulas and analysis methods used in this numerical analysis model). Will be described later). From the result of the numerical analysis model for a certain power plant basin, the relationship between the flow rate near the power plant and the total sand flow was obtained as a graph g5 shown in FIG.

From this graph g5, it can be seen that the coefficient is α = 1.0 × 10 ⁻⁶ in this power plant, and the total sand flow can be accurately predicted from the flow rate. By applying the coefficient α obtained above to Equation 3 above and using it, the total amount of sand transported to the vicinity of the power plant intake is predicted after Δt time (for example, 1 hour later) from the flow rate Q obtained by the tank model. it can. In addition, with reference to the value obtained by this numerical analysis, the accuracy of α is further improved by correcting the value that best reproduces the past record of the amount of sediment flowing into the power plant by trial and error.

  The calculation based on the above formulas 1 to 3 is also a calculation using a relatively simple formula and does not require calculation time according to a computer. For this reason, a quick calculation is sufficiently possible with general spreadsheet software. Therefore, by applying the hourly rainfall value of the Japan Meteorological Agency announced every hour to the upstream model as the upstream rainfall data, the power plant intake immediately after Δt time (for example, one hour later) It is possible to calculate the amount of river water transported to the river channel in front and the total amount of sand flow. FIG. 6 illustrates the calculation result g6.

--- About the second model (intake model) ---
Next, the intake port peripheral model as the second model will be described. As described above, by using the upstream area model, it is possible to predict the flow rate (water) transported from the upstream area to the river channel in front of the intake port and the total sand flow amount after Δt time based on the current rainfall. Therefore, in this intake model, as shown in Fig. 7, the sediment flowing into the river channel in front of the intake (the total amount of sand flowing together with the stream sand and floating sand) is deposited on the front of the intake and the sediment flowing into the intake. It is considered that it is divided into sediment and sand that flows down the dam. This is represented by the following four formulas (collectively, these are stored in the model database 125 as Formula 4: the second model formula). In order to predict the amount of inflow sediment at the power plant and determine whether to stop or resume intake, set the proportion of inflow sediment distributed to these three (φin, φout, φdp in Equation 4) in advance. It is necessary to keep.
Vin = φinVup
Vout = φoutVup
Vdp = φdpVup
φin + φout + φdp = 1
・ ・ ・ ・ ・ Formula 4

Therefore, φin, φout, and φdp in the above equation 4 are determined from the result of planar two-dimensional numerical analysis. Details of formulas and analysis methods for the planar two-dimensional numerical analysis will be described later. For example, for a river channel in front of an intake of a certain hydroelectric power plant, the flow rate from the upstream is constant at 200m ³ / s, the amount of sand flow and the amount of suspended sand are constant (calculated from Equations 3 and 4 at Q = 200m ³ / s) When the planar two-dimensional numerical analysis is performed under the conditions, the analysis result g8 shown in FIG. 8 is obtained. According to numerical analysis, with the passage of time (initial state → after 5 hours → after 10 hours → after 15 hours), there is a situation where sediment has accumulated in the front of the intake due to the supply of sediment from the upstream area and is flowing into the intake. It has been reproduced.

  From this analysis result, the amount of sediment flowing into the intake, the amount of sediment flowing downstream, and the amount of sediment deposited in the front of the intake can be calculated in time series. From these results, φin, φout, and φdp are calculated as shown in graph g9 in FIG. Yes, you can see that it fluctuates with time. φin is almost “0” at first, but increases after 2 hours and is generally constant after 6 hours. φout initially has a value of about “0.3”, but increases rapidly after 5 hours and is generally constant after 9 hours. φdp is a value of about “0.6” in the beginning, decreases rapidly after 5 hours, and is generally constant after 9 hours. The fluctuations in these values are due to the accumulation of sediment in front of the water intake over time. In the initial state, there is no earth and sand in front of the intake, so a large percentage of the sediment from the upstream accumulates in front of the intake. When a lot of sediment accumulates in front of the water intake over time, it becomes easy for soil to enter the water intake, and the amount of sediment flowing downstream after the intake dam increases, resulting in a decrease in the amount of sediment deposited. As described above, φin, φout, and φdp vary greatly depending on the amount of sediment deposited in front of the intake.

Therefore, the relationship between the amount of sediment deposited in front of the intake port and φin and φdp is shown in a graph g10 shown in FIG. In this figure, the horizontal axis represents the total sediment volume (Vdpsum) in front and divided by the total sediment volume (Vdpsummax) when the front of the water inlet is full. From the graph g10 in FIG. 10, for example, when the flow rate is 200 m ³ / s, φin, φout, and φdp can be set if the total amount of accumulated sediment on the front surface is known. In actual flooding, the flow rate is not constant and varies depending on the rainfall. Therefore, numerical analysis is performed under conditions of, for example, six patterns (50, 100, 150, 200, 250, 300 m ³ / s) for the flow rate, and the relationship between the sediment volume in front of the intake and φin, φout, φdp is shown in the graphs g11a and g11b illustrated in FIG. It is as follows. From the above relationship, the φin equation (Equation 5), the φout equation (Equation 6), and the φdp equation (Equation 7) are formulated as follows for easy calculation. These formulas 5 to 7 are stored in the model database 125 as the second model formula.
φin = ain · tanh (din × (Vdpsum / Vdpsummax−bin)) + cin
ain = MAX (27 × Q−1.2, 0.047)
bin = MIN (0.0035 × Q + 0.0745, 0.775)
cin = MAX (70 × Q−1.4, 0.047)
din = 15
・ ・ ・ ・ ・ ・ ・ ・ ・ Formula 5

φdp = MIN (0.6, 1.983 × (Vdpsum / Vdpsummax−0.3) +0.6)
・ ・ ・ ・ ・ ・ ・ ・ ・ Formula 6

φout = 1− (φin + φdp) Equation 7

  Since these formulas 5 and 6 differ depending on the power plant layout and riverbed material conditions, it is necessary to perform a two-dimensional planar analysis for each power plant to be studied. The graphs of the formulas 5 and 6 are also shown in the graph in FIG. The graphs according to the above formulas 5 and 6 generally agree with the numerical analysis results.

For example, when the actual flow rate was 75 m ^{3 /} s is, .phi.in of 50 m ^{3 /} s and 100 m ^{3 /} s was determined by the formula 5, 6, 7, .phi.out, may take the average of Faidp. By interpolating / extrapolating other flow rate values in the same manner, φin, φout, and φdp for the flow rate can be obtained. In order to increase the accuracy, the number of flow patterns to be studied may be increased.

By combining the above equations 4, 5, 6, and 7 with the upstream model described above, if the flow rate after Δt time and the current sediment volume (Vdpsum) at the intake front are known, Δt time from the present time The sediment that flows into the water intake can be predicted by the time later. The amount of sediment in front of the intake (Vdpsum) may be obtained by accumulating Vdp (= φdp × Vup) so far. Further, if the amount of sediment flowing into the intake port after the time Δt can be predicted, the total amount of sediment flowing in the intake port after the time Δt can be predicted by adding Vin to the total amount of sediment flowing into the intake port (Vinsum). Since simple mathematical formulas are used in the same way as the formulas for the upstream model, commercial calculation software can be used to calculate instantaneously even with a general personal computer, and the decision to stop or resume intake after Δt time at the power plant Can be used. For example, if Vinsum is set to “500 m ³ ” as the total inflow that will interfere with the operation of the power plant, intake stop processing will be performed when Vinsum after Δt time is predicted to exceed “500 m ³ ”. Execute.

On the other hand, even if the water intake is stopped during the water discharge period, if a large amount of earth and sand is accumulated in front of the water intake, the accumulated sediment may flow into the water intake after the water intake is resumed. This point needs to be taken into account when resuming water intake after stopping. Therefore, with the river flow and sediment volume of 100m ³ / s continuously given with the water intake stopped, the accumulated sediment volume is 200, 400, 600, 800, 1000 and 1150m ³ as the initial condition. A two-dimensional planar analysis was carried out under the conditions of a river flow rate of 20m ³ / s and maximum water intake simulating the time when water intake was resumed after flooding. FIG. 12 shows the relationship between the accumulated sediment inflow amount and the initial accumulated sediment amount in the front, and it can be seen that the sediment inflow amount after resuming water discharge increases as the accumulated sediment amount increases. When the water intake is resumed after the water intake is stopped, it is predicted that the amount Vafter using the equation 8 obtained from FIG. 12 from the front accumulated sediment amount at that time will further flow into the water intake. That is, Vafter is added to Vinsum.
Vafter = αaft × (Vdpsum / Vdpsummax) 2 + βaft × (Vdpsum / Vdpsummax)
... Formula 8
In this case, if the value obtained by adding Vafter when water intake is resumed to Vinsum does not exceed a certain reference value, water intake is resumed, and if it exceeds, sedimentary sediment is removed with heavy equipment before resuming water intake. Water intake may be resumed after there is no risk of inflow. Here, αaft = 406 and βaft = 19, but the accuracy can be further improved by correcting αaft and βaft with reference to the actually measured values.

  Next, a specific calculation method combining the upstream area model and the intake vicinity model will be described. Here, a prediction sheet (sheet of spreadsheet software for calculating the predicted value of intake inflow sediment volume) that combines the upstream area model and the intake vicinity model, and the above formulas are assigned to the predetermined cells of the prediction sheet. An example of (set as a function) is shown in FIG. In this prediction sheet g13, when the rainfall value at the present time is entered in the rainfall column together with the input time, the flow rate Q and the total sand flow VTL from the upstream area after Δt time (1 hour in this sheet) by the upstream area model. Is predicted. From the value of the total amount of sand drift, the total inflow soil volume Vup (= VTL × 3600) transported around the intake port per hour is predicted. In addition, φin, φout, and φdp can be calculated from the flow rate Q after one hour and the total amount of sediment in front of the intake port Vdpsum at the present time using the above formulas 5, 6, and 7. From this φin, φout, φdp and the total inflow sediment volume Vup, the sediment volume Vin, the downstream sediment volume Vout and the sediment sediment volume Vdp in the downstream of the intake port can be predicted by 1 hour later. By adding this Vin and the current intake total inflow sediment volume Vinsum, the Vinsum after 1 hour can be predicted. If it is found that Vinsum after 1 hour exceeds the preset limit value, water intake is stopped. If the limit value is not exceeded, water intake continues and power generation continues. In this case, since it is necessary when calculating φin, φout, and φdp at the next time (one hour later), Vdpsum after one hour is calculated by adding Vdp up to one hour later to the current Vdpsum. By repeating this process in the water, the amount of sediment flowing into the intake and the amount of frontal sediment in the water can be predicted in time series using the current rainfall as input data. When resuming the water intake after stopping the water discharge halfway, the sediment inflow amount Vafter is predicted by Equation 8 and added to Vinsum.

---- About numerical analysis ---
(1) Outline of numerical analysis model (upstream area) Nagai et al. (Both long and short-term spills) can be used to evaluate the outflow in the upstream area at the same time during flooding and normal conditions in order to evaluate the outflow in units of several months. For the standard constants of the model, we used a tank model for both long-term and short-term spills according to the Agricultural Civil Society Proceedings, No. 180, pp. 59-64, 1995. However, since it is necessary to evaluate the inflow from each tributary located in the basin here, a tank model was set for each slope divided into 60 basins. The flow in the upstream river channel is treated as an open channel one-dimensional unsteady flow. Formulas (1) and (2) shown in FIG. 14 were used as the basic flow equations.

  The bottom shear stress is evaluated by the Manning law. In order to differentiate the advection term of the momentum equation, the FDS method allows calculation of normal flow mixed flows (one-dimensional analysis of dam rupture flow, lectures on workshops using computers in water engineering, Japan Society of Civil Engineers, 1999.) Was used. For the amount of sand flow, we used the Kamata and Michigami formulas for each particle size in Eq. (3), and Egiazaroff and Asada in Eq. (4) as the movement limit. The formula of the laboratory report, general report No.2, 1976.) was used. For suspended sand, the continuous formula of suspended sand according to particle size of formula (5) was used. Here, Cbi was evaluated by equation (6).

  For example, a gravel bed river with a wide particle size distribution is assumed as a river in the river basin to be treated, and the floating sand floating amount from the river bed is Sekine et al. (Probability model for calculating equilibrium and non-equilibrium floating sand, As in No. 375 / II-6, pp. 107-116, 1986), the Hirota and Fujita formulas of formula (7) shown in FIG. 15 were used. Here, c, k are obtained by a function of the distance Δs from the top of the gravel to the fine sand filled in the gap of the gravel according to Tomita and Fujita. The continuous equation for the river bed was the equation (8) (Fig. 15), and the plain equation of the equation (9) (Fig. 15) was used for the change in the content of the particle size in the exchange layer. By discretizing the above basic equations and performing numerical analysis, it is possible to calculate the inflow of water and sediment from upstream rivers using rainfall as an input condition. An example of the calculation result is as shown in FIG.

(2) Outline of numerical analysis model (around intake) The sediment inflow phenomenon is reproduced by two-dimensional planar analysis around the intake of hydroelectric power plants. The basic model is a plane by Nagata et al. (Numerical calculation of planar two-dimensional unsteady flow using general curve coordinate system, Lectures on computer utilization in water engineering, Japan Society of Civil Engineers, pp. 45-72, 1999.) A two-dimensional analysis model was used. The basic flow equations were as shown in equations (10) and (11) shown in FIG. Moreover, the continuous formula of floating sand uses formula (12) shown in FIG. The floating sand floating amount from the riverbed is evaluated using the Kamata and Fujita formulas as in the upstream area. Furthermore, the equation (13) shown in Fig. 18 was used as the continuous equation for the riverbed, and the plain equation was used for the variation in the content of the particle size floor in the exchange layer as in the upstream region. As with the upstream model, the Kamata-Michigami equation was used for the evaluation of the amount of scavenging sand in the flow direction, and the Hasegawa equation was used for the amount of sand flow perpendicular to the flow direction.

  In such river bed fluctuation calculation process, the local topographic gradient at the front edge of the sand bar in front of the intake may be more than the angle of repose. In such a case, the terrain gradient between the grid and the four adjacent calculation grids is calculated for every grid in each calculation step, and if the local terrain gradient exceeds the repose angle, Sediment was instantaneously moved to the steepest adjacent grid so that the angle of repose with the adjacent grid became the angle of repose. When the riverbed collapses, the content of the collapsed depth range moves to the collapsed riverbed. By the above calculation, the flow around the intake of the hydroelectric power plant, river bed fluctuation and sediment inflow phenomenon can be reproduced. An example is shown in FIG.

  As described above, according to the present embodiment, it is possible to determine the timing of stopping / resuming intake, which obtains the maximum amount of generated power while suppressing the inflow of a large amount of earth and sand at the time of flooding in the inflow type hydroelectric power plant.

  As mentioned above, although embodiment of this invention was described concretely based on the embodiment, it is not limited to this and can be variously changed in the range which does not deviate from the summary.

5 Inflow Hydroelectric Power Station 6 Intake 7 Intake Dam 8 Sedimentation Sediment 9 Drainage Gate 100 Inflow Sediment Prediction System 101 HDD (Hard Disk Drive)
102 program 103 RAM (memory)
104 CPU (arithmetic unit)
105 Input Interface 106 Output Interface 107 NIC (Network Interface Card)
108 Flash ROM
109 Bridge 110 First means 111 Second means 112 Third means 113 Fourth means 118 OS
120 BIOS
125 Model database 160 Network 200 Rain gauge

Claims (6)

A method for predicting the amount of inflow sediment in a flow-through hydroelectric power plant,
For the rainfall in the upstream area of the intake river, the rainfall data of the rainfall observation station in the upstream area at the predetermined time is added to the first model formula that calculates the river water volume near the intake after the predetermined time and the sediment volume from the upstream. A first step of calculating the amount of river water and the amount of transported sediment in the vicinity of the intake after a predetermined time from the predetermined time;
Calculates the amount of sediment deposited before the intake and the amount of sediment flowing into the intake after a specified time, based on the values of river water, transported sediment, and existing sediment accumulated before the intake at the specified time. In the second model equation, the values of the river water amount, the transported sediment amount, and the existing sediment accumulation amount calculated by the first model equation are input, and the sediment accumulation amount before the intake and the intake to the intake after the predetermined time are input. A second step of calculating sediment inflow,
A third step of comparing the amount of sediment flowing into the water intake with a predetermined limit value, and specifying the time when the amount of sediment flow reaches the limit value as the water stop timing;
An inflow sediment prediction method characterized by comprising:   The inflow sediment prediction method according to claim 1, wherein in the third step, intake stop processing of the flow-in hydropower station is performed in accordance with the intake stop timing.   After the water intake stop process, the first step and the second step are continuously executed, and the amount of earth and sand flowing into the water intake at a certain point is compared with a predetermined reference value. The inflow sediment prediction method according to claim 2, further comprising a fourth step of specifying a time point lower than the value as a water resumption timing.   The inflow sediment prediction method according to claim 3, wherein in the fourth step, intake resumption processing of the flow-in hydroelectric power plant is performed in accordance with the intake resumption timing. A computer system for predicting the amount of inflow sediment in a flow-through hydroelectric power plant,
The first model formula for calculating the amount of river water near the intake after a specified time and the amount of transported sediment from the upstream for rainfall in the upstream area of the intake river, and the amount of river water and transported sediment near the intake at the specified time A storage device for storing a second model formula for calculating the amount of sediment deposited before the intake after a predetermined time and the amount of sediment flowing into the intake with respect to the amount and the value of the existing sediment accumulation before the intake;
The rainfall data of the rainfall observation station in the upstream area at a predetermined time is acquired by the input interface, and this rainfall data is applied to the first model equation read from the storage device, and near the intake port after the predetermined time from the predetermined time. The first step of calculating the amount of river water and the amount of transported sediment;
Applying the river water volume, transported sediment volume, and existing sediment volume calculated in the first step to the second model equation read from the storage device, the sediment volume before the intake after the predetermined time and A second step of calculating the amount of sediment flowing into the intake;
An arithmetic unit that compares the amount of sediment flowing into the water intake with a predetermined limit value, and performs a third step of identifying the time point when the amount of sediment flow reaches the limit value as the water stop timing;
An inflow sediment prediction system characterized by comprising: The first model formula for calculating the amount of river water near the intake after a specified time and the amount of transported sediment from the upstream for rainfall in the upstream area of the intake river, and the amount of river water and transported sediment near the intake at the specified time A storage device for storing a second model formula for calculating the amount of sediment deposited before the intake after a predetermined time and the amount of sediment flowing into the intake with respect to the amount and the value of the existing sediment accumulation before the intake; A computer equipped with a computing device for predicting the amount of inflow sediment in a flow-in hydropower plant,
A first step of inputting rainfall data at a rainfall observation station in an upstream area at a predetermined time into the first model formula, and calculating a river water amount and a transported sediment amount near the intake after a predetermined time from the predetermined time;
Into the second model formula, the values of the river water volume, the transported sediment volume, and the existing sediment volume calculated by the first model formula are input, and the sediment volume before the intake and the intake to the intake after the predetermined time are input. A second step of calculating sediment inflow,
A third step of comparing the amount of sediment flowing into the water intake with a predetermined limit value, and specifying the time when the amount of sediment flow reaches the limit value as the water stop timing;
An inflow sediment prediction program.