JPH0350114B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a flow rate control device for performing initial water flow treatment in a hydroelectric power plant.

[Technical background of the invention and its problems]

For example, some hydroelectric power plants controlled by a water level adjustment device are equipped with a flow rate control device that performs initial water flow processing. Figure 1 shows such a hydroelectric power plant. Upstream water flows into a reservoir 1 via a river or waterway, and this water is led to a water tank 4 through a water intake gate 2 and an unpressurized tunnel 3. Furthermore, the water in the water tank 4 drives a water wheel 6 via a guide vane 5, and is guided from a discharge channel 8 to a river or a lower pond. At that time, the generator 7 generates electricity by driving the water turbine 6.

Control of this hydroelectric power plant is performed as follows. That is, the water level 10 of the water tank 4 is detected by a water level detector and inputted to the water level adjustment device 11. On the other hand, the water level adjustment device 11 returns the guide vane opening degree 14 and outputs a guide vane operation command 12 to the guide vane 5 so that the water tank water level 10 is maintained at a predetermined level. This is the flow control device 15
It is output on the condition that the start command 13 of the main engine (hydraulic turbine, generator) is issued.

On the other hand, a reservoir water level 18 detected by a reservoir water level detector 17 and a command flow rate 16 are input to the flow rate control device 15, and a gate operation command 22 for the water intake gate 2 is issued based on these. As a result, the operation motor 19 is operated, and the gate opening degree 21 is detected by the gate opening degree detector 20 and fed back to the flow rate control device 15 . In this way, the outflow amount 23 of water from the reservoir 1, the inflow amount 24 of water into the water tank 4, and the outflow amount 25 of water from the water tank 4 are controlled, respectively.

FIG. 2 is a characteristic diagram showing the relationship between the command flow rate 16 when performing the initial water flow and the actual flow rate (initial water flow amount) 40 of water during the initial water flow. a ₀ indicates the upper limit of the initial water flow rate of 40. Command flow rate 16
is less than a ₀ , the command flow rate 16 is the initial water flow rate 4
0, and if the command flow rate 16 is larger than a ₀ , the initial water flow rate 40 is suppressed to the upper limit a ₀ of the initial water flow rate, as can be seen from the figure.

Assuming that the command flow rate 16 changes from 0 to a ₁ (a ₁ >0), the flow rate control device 15 controls the water intake gate 2.
A gate operation command 22 is given to the operation motor 19. This gate operation command 22 opens the water intake gate 2 from the gate fully closed state to the gate opening degree corresponding to the commanded flow rate 16, so that the amount of water flowing out from the reservoir 1 becomes the same as the commanded flow rate 16. However, in order to control the water intake gate 2 so that the commanded flow rate is 16 at this time, the following needs to be considered.

One is the change in the water tank water level 10 when the water tank 4 is not very large in a hydraulic plant, and the other is,
Since the reservoir 1 and the water tank 4 are connected by the unpressurized tunnel 3, it takes a predetermined time (landing time) for the water that has passed through the water intake gate 2 to flow into the water tank 4. Plants that need to take these into account are required to operate in the following manner. Since the water tank 4 is not very large, if the difference between the inflow amount 24 and the outflow amount 25 of water becomes large, the change in the water level 10 of the water tank becomes drastic, resulting in an overflow or a drop in the water level, leading to the generator being stopped. Therefore, the above initial water flow treatment is performed. Here, in order to keep the tank water level stable especially when the capacity of the water tank is small, we will describe the process of first starting the main engine and canceling the restriction on the commanded flow rate while the water is being adjusted. Command flow rate 1 from gate fully closed
When opening the water intake gate 2 to the gate opening degree corresponding to 6, the water intake gate 2 first sets the outflow amount 23 of water from the reservoir 1 to a certain value a ₀ or less.

The initial forecast is calculated by taking into account the landing time of the water that has passed through the water intake gate 2 and the time required for the water tank 4 to stabilize so that the inflowing water is less turbulent and can be used for the water level adjustment device 11. The startup waiting time is determined in advance so that the startup of the main engine coincides with the water time.
This waiting time for starting the main engine is defined as "0" at the moment when the water intake gate 2 starts to open from the fully closed state, and is the waiting time from that moment until starting the main engine starts.
When the main engine startup waiting time has elapsed, the flow control device 1
5 outputs a main engine start command 13 to the water level adjustment device 11.

Then, the main engine is started by this main engine start command 13, and after the start time for accelerating and synchronously joining the water turbine has elapsed, the water level adjustment device 11 starts water adjustment operation. When the water adjustment operation starts, the water level adjustment device 11 drives the guide vane 5 according to the guide vane operation command 13 so that the inflow amount 24 and the outflow amount 25 of water into the water tank 4 become constant. In this state, the water level 10 of the water tank 4 becomes stable.

Therefore, after that, the flow rate control device 15 drives the gate operation motor 19 so that the commanded flow rate 16= _a1 , which is the final target, is achieved. Then a ₁ −
Even if a ₀ is large to some extent, the water level adjustment device 15 drives the guide vane 5 according to the change in the tank water level 10 without any startup time, so the amount of water flowing into the tank 4 24
The difference between the flow rate and the outflow amount 25 does not become too large.
Therefore, the plant can be operated without causing problems such as overflow.

In the above process, when it is detected that the command flow rate has changed from 0 to a value larger than 0 with the water intake gate 2 fully closed, the flow rate to be restricted for a predetermined time is the initial water flow rate, initial water landing time + water system The above-mentioned predetermined time for stabilization, etc. is the initial water flow time. In addition, the above explanation describes the process of canceling the command flow restriction after water adjustment operation by starting the main engine, but the size of the water tank,
There is a permissible range for water level fluctuations in the aquarium due to inclination, etc. Therefore, in order for the main engine to start water conditioning operation within this allowable range of time, the start command is set to be output from this time before the startup time required for starting the main engine, and from the initial water flow detection, this main engine starts. The time it takes for the main engine to start is the waiting time for starting the main engine.

In other words, during the initial water flow time, the opening of the water intake gate is controlled so that the initial water flow rate is the same as the command flow rate with restrictions, and the water adjustment operation is performed within the allowable range of the initial water flow time depending on the water system characteristics of each power plant. The process of outputting a start command and controlling the start of the main engine after a predetermined start waiting time is collectively referred to as the initial water flow process.

A schematic configuration of the flow rate control device 15 that performs this initial water flow process is as shown in FIG. 3. That is, the processing contents such as calculations that are performed during the period from when the command flow rate 16 changes from 0 to a certain value and the initial water flow process ends until the water outflow amount 23 from the reservoir 1 reaches the command flow rate 16 are as follows. It is.

First, when the gate opening degree 21 is fully closed and the command flow rate 16 becomes a value larger than 0, the initial water flow detector 28 detects the initial water flow state. When the initial water flow state is detected, the initial water flow detector 2
8 outputs an initial water flow command 34. Based on this initial water flow command 34, the gate opening target value 36 is calculated by the calculator 30 based on the initial water flow rate 40 which is the commanded flow rate 16 limited by the limiter 29 and the reservoir water level 18 at that time.
Calculate. Then, by adjusting the adjuster 31, this gate opening degree target value 36 and the actual gate opening degree target value 21 are adjusted.
If the deviation is greater than the dead zone of 32, the gate operation command 22 is sent to the gate operation motor 19.
and controls the water intake gate 2 so that the outflow amount 23 of water from the reservoir 1 becomes the initial water flow amount 40.
This initial water flow state continues for the initial water flow time 27 set in the setting device 26, and after that time, the initial water flow detector 28 detects the end of the initial water flow process and issues an initial water flow command 34. unlock. Upon cancellation, the start command generator 35 outputs the main engine start command 13 to the water level adjustment device 11. By canceling this initial water flow command 34, the command flow rate 16 is directly changed to the calculator 3.
0 is input, a new gate opening degree target value 36 corresponding to this value is calculated, and the water intake gate 2 is controlled with this as the target, so that water similar to the command flow rate 16 flows out from the reservoir 1.

By the way, the initial water flow time used here takes into account the water landing time and the water system stabilization time, as described above. This water landing time is determined by the length, slope, shape, surface condition, gravity, flow rate, etc. of the unpressurized tunnel, and the water system stabilization time is mainly determined by the shape of the water tank 4, the flow rate flowing into the tank, and the tank water level. Determined by etc. Here, each value other than flow rate and water level differs for each plant, but the plant itself hardly changes over time.
Therefore, the initial water flow time is usually determined by taking into consideration the water landing time and water system stabilization time at a certain flow rate.

Then, the time is set in the setting device 26. However, in this case, it is difficult to select the flow rate for determining the initial water flow time. At flow rates other than that flow rate, the water landing time etc. differ and the timing of starting the main engine is too early or too late compared to the actual water landing time, resulting in unstable control. In addition, in order to prevent such instability of control, there is a drawback that the initial water flow rate must be controlled at a constant flow rate, which does not allow for much margin.

[Purpose of the invention]

The purpose of the present invention is to reduce the instability of control caused by the difference in the initial water flow rate and the time difference between the main engine startup time and the actual initial water flow time, and to reduce margins such as limitations on the initial water flow rate. It is an object of the present invention to provide a flow rate control device suitable for performing initial water flow treatment without the conventional drawback of having to perform unnecessary control.

[Summary of the invention]

The present invention uses the initial water flow rate as a state quantity that changes the water landing time, etc., adds a new computing unit that calculates the initial water flow time based on the flow rate, and uses the result of the computing unit as the initial water flow time. To provide a flow rate control device suitable for performing initial water flow processing, which eliminates the deviation in timing of starting a main engine seen in the past by using it, performs stable control, and can also change the initial water flow amount.

[Embodiments of the invention]

The configuration diagram of the flow rate control device of the present invention is shown in FIG.
Further, FIG. 5 shows an example of the input/output characteristics of the arithmetic unit used in the present invention to calculate the initial water flow time.

In FIG. 4, the same components as those in FIG. 3 are designated by the same reference numerals, and their explanation will be omitted. Reference numeral 50 indicates an initial water flow time calculation calculator newly added according to the present invention, and 51 indicates an initial water flow time calculated by the calculator 50. Further, 150 is a flow rate control device of the present invention. Note that this calculator 50 stores a characteristic curve based on a mathematical formula or actual data indicating the relationship between the initial water flow amount 40 and the initial water flow time 51. Then, the computing unit 50 outputs an initial water flow time 51 corresponding to the initial water flow amount 40 as shown in FIG.

Control is completed from the initial water flow start using Figures 4 and 5 below (takes the same flow rate as command flow rate 16)
The processing performed up to this point will be explained. First, the initial water flow detector 28 detects the initial water flow state and outputs the initial water flow command 34. next,
A gate opening degree target value 36 is calculated by a calculator 30 based on the flow rate (initial water flow rate 40) obtained by adding a limiter 29 to the command flow rate 16 based on the initial water flow command 34 and the reservoir water level 18 at that time. At this time, Limituta 2
Since the restriction by 9 is configured to limit the upper limit value, initial water flow can be performed by inputting any value as the command flow rate 16 as long as the flow rate is less than the upper limit value. Moreover, if the upper limit value is configured to be changeable, the initial water flow amount can be set to an arbitrary value.
However, since the upper limit of the initial water flow rate is determined by the stability of the water system of each plant, initial water flow cannot be performed at a higher flow rate.

Next, the deviation between the gate opening degree target value 36 and the actual gate opening degree 21 is determined by the adjuster 31. deviation is 3
If the dead zone is greater than 2, a gate operation command 22 is output to the gate operation motor 19. The water intake gate 12 is driven by this operation motor 19, and the outflow amount 23 of water from the reservoir 1 is controlled so as to be an initial water flow amount 40. Based on this initial water flow amount 40, the initial water flow time 51 at that time is calculated. For the calculation, an arithmetic unit 50 as shown in FIG. 5 is used.

The initial water flow state is continued during this initial water flow time 51, and after that time, the initial water flow detector 28 detects the end of the initial water flow process and cancels the initial water flow command 34. When this initial water flow command 34 is canceled, the start command generator 35 outputs the main engine start command 13 to the water level adjustment device 11, and the water level adjustment device 11 controls the guide vane 5 to control the water tank 4.
The outflow amount 25 of water from the tank is made to flow according to the water tank water level 10. At the same time, the command flow rate 16 is directly input to the calculator 30.
Enter. Then, a new gate opening degree target value 36 corresponding to the command flow rate 16 is calculated, and control is performed with this new gate opening degree target value 36 as the target.

As described above, the flow rate control device of the present invention performs initial water flow for an initial water flow time corresponding to the initial water flow amount, and outputs a start command for the main engine. This eliminates the timing lag between the main engine start-up, water landing time, and water system stabilization time that was conventionally seen, making it possible to perform stable control. In addition, the initial water flow amount, which was fixed in order to prevent the above-mentioned timing deviation, can be changed freely as long as it is within the water system constraints.

In the above example, only the initial water flow rate was used to calculate the initial water flow time, but in plants where the stability of the water system is considered as important or more important than the water landing time, the tank water level and the initial water flow rate may be used. Use this to calculate the initial water flow time. In addition, if a specific plant has other state variables that change the initial water flow time, the initial water flow time is calculated using the state quantities.

〔Effect of the invention〕

As described above, according to the present invention, the initial water flow time is calculated based on the predetermined state quantity at that time, and the initial water flow processing and the start-up command for the main engine are performed, so that stable control can be performed. Further, since restrictions on control such as the initial water flow amount can be reduced, a flow rate control device suitable for performing initial water flow can be provided.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a hydroelectric power plant that includes a flow rate control device that performs initial water flow processing, Figure 2 is a diagram showing the relationship between commanded flow rate and initial water flow rate, and Figure 3 is a schematic diagram of the configuration of a conventional flow rate control device. , FIG. 4 is a schematic diagram of the configuration of the flow rate control device of the present invention, and FIG. 5 is a characteristic diagram showing an example of input/output characteristics of a computing unit that calculates the initial water flow time. 1... Reservoir, 2... Water intake gate, 3... Unpressurized tunnel,
4... Water tank, 5... Guide vane, 6... Water wheel, 7... Generator, 8... Waterway, 9... Water tank water level detector, 10...
Water tank water level, 11...Water level adjustment device, 12...Guide vane operation command, 13...Main engine startup command, 14...Guide vane opening degree, 15...Conventional flow rate control device, 1
6...Command flow rate, 17...Reservoir water level detector, 18...
Reservoir water level, 19... Gate operation motor, 20...
Gate opening degree detector, 21... Gate opening degree, 22... Gate operation command, 23... Outflow amount of water from the reservoir,
24... Amount of water flowing into the aquarium, 25... Amount of water flowing out from the aquarium, 26... Initial water flow time setting device, 27...
Initial water flow time, 28...Initial water flow detector, 29...Limiter of command flow rate, 30...Arithmetic unit for gate opening target value calculation, 31...Adjuster for deviation calculation, 32...Dead zone, 33...Motor gate opening Characteristics, 34...Initial water flow command, 35...Start command generator, 36...Gate opening target value, 40...Initial water flow rate, 50...Arithmetic unit for calculating initial water flow time, 51...Initial water flow time, 150...
Flow control device of the present invention.

Claims (1)

[Claims] 1 In a flow rate control device that controls the opening of the intake gate and the start-up of the main engine with restrictions during the initial water flow time due to initial water flow processing in a hydroelectric power plant, the initial water flow time is determined by the flow rate during the initial water flow. What is claimed is: 1. A flow rate control device comprising: a calculation section for calculating , and performing the initial water flow processing using the initial water flow time that is a result of the calculation section.