JP4339199B2 - Water intake control method and water intake control system for flow-type hydroelectric power plant - Google Patents

Description

  The present invention relates to a water intake control method and a water intake control device for an inflow-type hydroelectric power plant installed adjacent to a river flowing through a mountainous area.

  Hydropower plants generally have a method of storing river water in a dam installed across the river and generating power using this water. However, the river water is branched using a dam or the like. There are also a number of inflow types that generate power by guiding water into an artificially constructed channel and dropping the water in a hydraulic iron pipe installed on an inclined surface such as a mountainside. The flow-type hydroelectric power plant has a dam installed so as to cross the river, the water stored here is sent to the intake through the water inlet control gate, and further sent to the hydraulic iron pipe through the sand basin, The water that falls inside the hydraulic iron pipe rotates the water wheel to drive the generator. The water that has turned the water wheel is returned to the river from the discharge channel, and the sand accumulated in the sand basin can be returned to the river using the sand discharge channel.

  Various foreign substances such as driftwood and stones are mixed in the river, and if these foreign objects enter the flow-in hydroelectric power plant, the facilities of the power plant may be damaged. In order to prevent large foreign objects from entering the intake from the river, a grid-like frame called an intake screen is installed on the entrance side of the intake control gate to prevent driftwood and rocks from entering, and before the hydraulic iron pipe. The installed aquarium screen can remove fine foreign substances such as leaves. Since sand cannot be removed by both screens, the flow rate of water is reduced in the sand basin and settled at the bottom.

  The river water used for power generation contains some amount of sand even after passing through the sedimentation basin, and this sand touches the hydraulic iron pipes and turbines and gradually wears the surface. And maintenance has been done. And when heavy rain falls upstream of the power plant, the amount of water in the river increases, sand in the basin and the bottom of the river is rolled up and becomes muddy, and these also flow into the power plant. Since such turbidity cannot sufficiently separate the sand even in the sand basin and wears water turbines, etc., when the amount of water in the river has increased, conventionally, the intake control gate is closed and the intake is stopped. When the amount of water decreases over time, the intake control gate is opened and water intake is resumed.

  However, the amount of water and the amount of sand in the water are not necessarily closely related, and if the amount of water is more than normal but the amount of sand is low, the intake control gate can be closed even if the water can be resumed. If there is a landslide in the upstream, a large amount of sand flows in regardless of the amount of water, which may cause serious damage to the equipment. Therefore, if the power plant is operated only depending on the amount of water, water intake may be stopped when power generation is possible, or water intake may be continued when power generation should be stopped. Problems such as a reduction in the operating rate of the plant.

  The present invention was developed on the basis of such a situation, and considering the amount of water as well as the sand contained in river water, it is possible to reduce damage to the power plant equipment and to improve the operating rate of the power plant. The purpose is to provide a water intake control method and a water intake control device for a hydroelectric power plant.

The invention according to claim 1, which solves the above problem, measures turbidity in the river adjacent to the intake control gate and the amount of water in the river, and when the intake control gate is opened , the turbidity is turbid. When the intake control gate is closed and the intake is stopped when it exceeds the upper limit, the intake control gate is closed intermittently if the water volume is less than the specified flow rate , and the intake control gate is closed. In this case , when the turbidity is equal to or lower than the lower limit of turbidity, the intake control method of the flow-type hydroelectric power plant is characterized in that the intake control gate is opened and water intake is resumed.

  A flow-type hydroelectric power plant has conventionally been equipped with a water level detector that detects the water level in the dam, and is used for control by calculating the amount of water in the river from the water level. In the present invention, in addition to the water level detector, a turbidimeter is installed to measure the turbidity of the water in the dam, and these data are continuously transmitted to the control unit that supervises the water intake. Has been. When the river level is normal, the intake control gate is open, and the water stored in the weir passes through the intake screen and intake control gate and is taken into the intake, and the water pressure passes through the sand basin. It is sent to an iron pipe to drive a water wheel to generate electricity.

When there is rainfall in the upstream part of the river and the river increases, the sand of the mountain surface and the bottom of the river mixes with the water stream and enters the weir, but the turbidity of the river water is continuously measured, and this value is When the specified turbidity upper limit is exceeded, the intake control gate is closed and the intake stopped regardless of the river flow rate. When the amount of water exceeds a predetermined upper limit of flow rate, the intake gate is closed and the intake is stopped regardless of the turbidity as in the conventional case. The turbidity upper limit is an eigenvalue determined for each power plant based on empirical rules and results obtained from experiments, and the other upper limit is the eigenvalue determined based on the allowable water volume of intake facilities. . Therefore, the condition for stopping the water intake is when either the turbidity or the amount of water exceeds the standard, and even when a large amount of sand flows into the river at once due to landslides, the water intake can be stopped quickly. In addition, when water intake is stopped, if the amount of water is less than the specified flow rate, the intake control gate is lowered intermittently to prevent rapid water increase in the downstream area. This specified flow rate is different from the previous flow rate upper limit value and is a value for determining whether the intake control gate is lowered intermittently or continuously.

  Even when the above conditions are satisfied and the intake gate is closed, when the time elapses after the rainfall ends, both the amount of water and turbidity decrease, and the water intake can be resumed. As conditions for resuming water intake, it is essential that the amount of water is below the upper limit of the flow rate, and the turbidity is equal to or lower than a predetermined lower limit of turbidity. This turbidity lower limit value is not the same as the above turbidity upper limit value, and is a smaller value. With regard to turbidity, conditions for resuming water intake are more severe than conditions for stopping water intake. In addition to the turbidity lower limit value, the flow rate lower limit value is determined in the same manner as in the prior art, and water intake can be resumed even when the amount of water falls below the flow rate lower limit value. In this way, in the past, resumption of water intake was determined only by the amount of water, but by taking account of turbidity according to the present invention, water intake can be resumed at an earlier point when the turbidity of river water is rapidly improved. .

  The turbidimeter is used for various water quality surveys, and measures the turbidity by an optical method based on the turbidity of a standard solution. This measured value is expressed as 100 degrees or the like. The measurement result is converted into an electrical signal and can be directly input to a computer or the like, which is transmitted to a control unit that manages the intake and used for operation of the intake facility. In the present invention, in order to accurately measure the turbidity of the river, the turbidimeter needs to be installed in the river around the intake control gate. However, the turbidimeter is a precision instrument, and if installed alone, driftwood There is a risk of damage due to foreign matter such as, and protective measures such as covering the turbidimeter with a metal pipe are necessary. The location of the turbidimeter is not limited, but it is necessary to avoid places where water is stagnant so that correct measurement can be performed, and to give sufficient consideration not to be affected by fluctuations in the water level.

The invention described in claim 2 is a remote control intake intake gate, a turbidity meter for measuring turbidity in a river adjacent to the intake control gate, and a river level adjacent to the intake control gate. When the water level detector to be measured , the turbidity from the turbidimeter and the water level from the water level detector are received and the intake control gate is opened , the turbidity exceeds the turbidity upper limit value and the intake port When stopping the intake by closing the water control gate, if the amount of water converted from the water level is less than the specified flow rate, the water intake control gate will be lowered intermittently, and when the water intake control gate is closed , This is a water intake control device for a flow-type hydroelectric power plant that includes a control unit having a function of opening a water intake control gate when the degree becomes lower than the turbidity lower limit value.

In order to realize the method according to claim 1, a water intake control device as described in claim 2 is required, and the water intake control gate has a function of opening and closing the water channel by remote control from the control unit. The turbidity measured by the turbidimeter and the water level measured by the water level detector are also transmitted to the control unit. The control unit can automatically stop or restart the intake by operating the intake control gate by a program incorporated based on information such as turbidity and water level.

As in the first and second aspects of the invention, in addition to the conventional river water volume, turbidity is newly used as a criterion for determining the opening and closing of the intake control gate. If the wear of water turbines, etc., is expected to increase rapidly, closing the intake control gate early and stopping the intake will prevent problems due to damage to the power generation equipment, and the sediment in the sand basin The increase in the maintenance cost can be suppressed, and the cost and labor for maintenance inspection can be reduced. Furthermore, when the peak of water increase is passed, by incorporating turbidity into the conditions for resuming intake, the intake control gate can be opened at an earlier stage than before, and an improvement in the operating rate of the power plant can be expected. In addition, when stopping water intake, if the amount of water is less than the specified flow rate, the intake control gate is lowered intermittently, so that rapid water increase in the downstream area can be prevented and human damage can be avoided.

  FIG. 1 is a plan view showing a configuration example of a flow-type hydroelectric power plant according to the present invention. First, a dam 2 and a sand discharge gate 3 are installed so as to cross a river 1. River water is blocked by the dam 2, but part of it overflows from the dam 2 and flows downstream. In addition, the sand discharge gate 3 is opened when discharging the sediment accumulated in the dam 2. A water intake 6 for taking in water from the dam 2 is installed adjacent to the river 1, and a water intake screen 4 is installed at the boundary between the river 1 and the water intake 6 to prevent the ingress of driftwood and rocks. Next, a water intake control gate 5 for adjusting the intake of water is installed, and when it is opened, water flows into the water intake 6 and when it is closed, the water stops. The water that has passed through the water intake 6 flows into the sand settling basin 7, where the flow path width widens and the flow velocity decreases, so that the sand sinks to the bottom, and then the water is sent from the water conduit 8 to the water tank 9. The water tank 9 is a facility for temporarily storing water prior to power generation, and since the flow velocity is reduced here, the remaining sand settles. The water stored in the water tank 9 passes through the water tank screen 10 excluding foreign matters such as fallen leaves, falls in the hydraulic iron pipe 11 installed on the slope, rotates the water wheel 12, and returns to the river 1 from the water discharge channel 14. Further, the water turbine 12 drives the generator 13 to generate electric power. The sand accumulated in the sand basin 7 and the water tank 9 is returned to the river 1 by opening the drainage sluice gate 16 and using the sand discharge channel 17. In addition, a water level detector 18 is installed in the vicinity of the intake screen 4 in order to detect the water level in the dam 2. In addition to these, the auxiliary sluice 15 installed at the exit of the settling basin 7 and the water tank 9 is used at the time of maintenance and inspection.

  The configuration so far is the same as that of a conventional inflow type hydroelectric power plant, but in the present invention, a turbidimeter 20 is installed adjacent to the intake screen 4 in order to measure the turbidity in the river 1. In order to prevent damage due to collision with a foreign object, a large number of holes are provided in the surface of the metal pipe and are accommodated in a protective member 19 that can take in water. In addition, a control unit 21 that manages intake facilities is installed in the vicinity of the intake port 6. Information is collected from sensors installed in various places, and operation is performed based on the information. The measured values of the water level detector 18 and the turbidimeter 20 are immediately converted into electric signals and continuously transmitted to the control unit 21. Each sluice can be remotely operated from here.

  FIG. 2 is a block diagram showing a configuration of the control unit 21 and devices connected thereto. Although the control part 21 manages various intake facilities and incorporates various information, only the elements relevant to the present invention are shown in the figure. Like a general computer, the control unit 21 is composed of a CPU that performs information processing and various storage devices that store information, collects data from sensors installed in various places, and processes them with a predetermined program. Based on this result, driving is automatically performed. As shown in the figure, the control unit 21 constantly receives measurement values from the water level detector 18 and the turbidimeter 20, and the intake control gate 5 is opened and closed based on the determination of the control unit 21. The water level detector 18 simply detects the water level, and the actual amount of water takes into account the opening of the sand removal gate 3 installed adjacent to the dam 2 as well as the cross-sectional shape and flow velocity of the river 1. And calculated by the control unit 21.

  FIG. 3 is a flow diagram showing an example of an operation method of the intake control gate 5 according to the present invention, and shows the conditions for stopping the water intake. FIG. 3 (A) is a flow according to the present invention, and FIG. ) Is a conventional flow. From the detection value of the water level detector 18, the amount of water is converted by the control unit 21 in consideration of the opening degree of the sand removal gate 3 as described above. This amount of water is in a state before branching to the water intake 6, and the amount of water after water intake is lower than this. For the turbidity, the numerical value transmitted from the turbidimeter 20 is directly used. The flow described in FIG. 3 (A) is according to the present invention. When the turbidity upper limit value or more continues for a certain time, the intake control gate 5 is closed. At this time, if the amount of water in the river 1 does not reach the specified flow rate, the water intake will stop and the downstream of the dam 2 will rapidly increase from the normal state, causing concern about human damage. The intake control gate 5 is lowered intermittently so that it can be done.

  In addition, the flow in FIG. 3B is a standard that is provided so as to prevent a large amount of foreign matter from flowing in and to prevent an allowable water amount from being exceeded when water intake is stopped due to the amount of water conventionally used. Here, the upper limit of the flow rate at which water intake is stopped is defined, and when this continues for a certain period of time, the water intake control gate 5 is closed regardless of the turbidity, and water intake is stopped. In addition, since the dam 2 is completely submerged at the time of water increase, the water level detector 18 and the like are also installed at a height corresponding to this.

  Even after the condition as shown in FIG. 3 is established and the intake control gate 5 is closed, the water level detector 18 and the turbidimeter 20 measure the state of the river 1 every moment, and determine when to resume. . FIG. 4 is a flow showing the conditions for resuming intake, and FIG. 4 (A) uses turbidity according to the present invention. When the lower turbidity value continues for a certain period of time, the intake control gate 5 is opened. Open and resume water intake. However, even if the turbidity satisfies this criterion, it cannot be resumed as long as the amount of water is not less than the upper limit of the flow rate. Moreover, water intake can be resumed also when it becomes below a flow volume lower limit as shown in FIG.4 (B).

  The upper limit of turbidity shown in Fig. 3 and Fig. 4 varies depending on various factors such as river conditions, seasons, power plant scale, etc., so it is necessary to determine the optimal value through tests for each power plant. . In addition, since turbidity and water volume are pulsating and are not constant, measures are taken so that these values are continuously measured for several seconds to several minutes to eliminate sudden fluctuations.

From previous studies, it has been found that the situation in which various facilities in contact with the water flow such as the water turbine 12 are worn by sand or the like can be approximated by the following equation.
W = K × a × ρ × V ³
Here, each variable is as follows.
W: Wear rate of water turbines (mm / h), K: Constant calculated by results survey,
a: average particle diameter (mm), ρ: earth and sand concentration (g / L), V: flow velocity (m / s).
Here, since the flow velocity is determined by the difference in the height of the hydraulic iron pipe, it is almost constant regardless of the amount of water in the river. The constant is unique from the results for each power plant, and the remaining a × ρ value is This a × ρ is hereinafter referred to as water quality for convenience. To actually measure this water quality, it is necessary to extract a sample from river water, separate suspended matter with filter paper and measure the weight, or take out multiple particles and measure the diameter with a microscope etc. .

  FIG. 5 is a graph showing the investigation results of the relationship between the water quality and turbidity, and the relationship between the water quality and the amount of water in the river, which was performed in the development stage of the present invention. FIG. 5 (A) shows the relationship between the water quality and the indicated value (turbidity) of the turbidimeter, and thus there is a strong correlation between the water quality and turbidity. Therefore, since the wear rate of the equipment increases as the turbidity increases, the method of stopping and restarting water intake with the turbidity is effective for maintenance of the equipment. On the other hand, FIG. 5B shows the relationship between the water quality and the amount of water in the river. Since the water quality involves various factors such as upstream vegetation and rainfall history, the correlation between the water quality and the water amount is sparse.

  FIG. 6 is a graph showing the results of measuring, in a time series, the turbidity measured by the turbidimeter 20 and the amount of water converted based on the water level detector 18 at a certain inflow type hydroelectric power plant. . Here, FIG. 6 (A) shows the case where the present invention is applied to the measurement result to stop and restart the water intake, and FIG. 6 (B) shows the case where the conventional method is applied to the same measurement result. Show. The horizontal axis of these graphs shows the passage of time (one scale is half a day), and the vertical axis is turbidity and water volume. From this measurement result, when the water increase starts, the turbidity increases as the water volume increases, but after the water volume has passed the peak, the water volume gradually decreases, whereas the turbidity is more rapid. It can be seen that it decreases. Therefore, if the intake control gate 5 is opened and closed based on the turbidity, when the water increases, the inflow of sand can be reduced by stopping water intake earlier than when the amount of water is used as a reference, and after passing the peak, Water intake can be resumed early by taking advantage of the rapid decline in turbidity.

  As in the flow shown in FIG. 3 (A) and FIG. 4 (A), FIG. 6 (A) stops water intake when the turbidity is equal to or higher than the turbidity upper limit value, and falls below the lower turbidity lower limit value. The water intake is resumed at the time. From this graph, it can be seen that FIG. 6 (A) using turbidity has reached the standard for stopping water intake at an earlier time point. Therefore, since the amount of sand flowing into the power generation facility can be reduced, there are advantages in terms of maintenance and inspection such as sand accumulation in the sand settling basin 7 and wear of the water turbine 12.

  In addition, when turbidity is used as a reference as shown in FIG. 6 (A), it can be seen that water intake has been stopped for about 6 hours. On the other hand, FIG. 6 (B), like the flow shown in FIG. 3 (B) and FIG. 4 (B), stopped taking water when the amount of water became equal to or higher than the upper limit of flow rate, and became equal to or lower than the lower limit of flow rate. Water intake is resumed at that time. From this graph, it can be seen that when the operation is performed based on the amount of water, water intake is stopped for about 7 hours. Therefore, by using turbidity, the abundant amount of water after rainfall can be used effectively, and the operating rate of the equipment is improved.

It is a top view which shows the structural example of the inflow type hydroelectric power station by this invention. It is a block diagram which shows the structure of a control part and the apparatuses connected to this. The flow diagram which shows the example of the operating method of the intake control gate by this invention shows the conditions at the time of stopping intake, (A) is the flow based on the turbidity by this invention, (B) is conventional The flow is based on the amount of water. The flow diagram which shows the example of the operating method of the intake control gate by this invention shows the conditions at the time of resuming intake, (A) is the flow based on the turbidity by this invention, (B) is conventional The flow is based on the amount of water. (A) shows the relationship between the water quality and turbidity, and the relationship between the water quality and the amount of water in the river. (A) shows the relationship between the water quality and the turbidity indicator value (turbidity). The relationship with the amount of water in the river is shown. It is a graph showing the result of measuring the turbidity measured by a turbidimeter and the amount of water converted based on a water level detector in a time series at a certain inflow type hydroelectric power station, (A) (B) shows the case where the conventional method is applied to the same measurement result when the present invention is applied to the measurement result to stop and restart the water intake.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 River 2 Barrage 3 Drainage gate 4 Water intake screen 5 Water intake control gate 6 Water intake 7 Sand basin 8 Waterway 9 Water tank 10 Tank screen 11 Hydraulic iron pipe 12 Water wheel 13 Generator 14 Drainage channel 15 Auxiliary water gate 16 Drainage gate 17 Sand discharge channel 18 Water level detector 19 Protective member 20 Turbidity meter 21 Control unit

Claims (2)

When measuring the turbidity in the river (1) adjacent to the intake control gate (5) and the amount of water in the river (1) and opening the intake control gate (5) , the turbidity is the upper limit of turbidity When the intake control gate (5) is closed and the intake is stopped when the value exceeds the specified value, the intake control gate (5) is lowered intermittently and the intake control gate ( 5) When the turbidity falls below the lower limit of turbidity when closed, the intake of the flow-through hydroelectric power plant is characterized by opening the intake control gate (5) and restarting the intake. Control method. A water intake control gate (5) capable of remote control, a turbidimeter (20) for measuring turbidity in the river (1) adjacent to the water intake control gate (5) , and a water intake control gate (5) A water level detector (18) for measuring the water level of the river (1) adjacent to
Receives water from the turbidity and water level detector (18) from the turbidity meter (20), when being opened intake system sluice (5), turbidity becomes higher turbidity limit When the intake control gate (5) is closed and the intake is stopped, the intake control gate (5) is lowered intermittently if the water volume converted from the water level is less than the specified flow rate. When the turbidity is equal to or lower than the lower limit of turbidity when (5) is closed, the control unit (21) having a function of opening the intake control gate (5) is provided. Intake control device for hydroelectric power plant.

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