JPH06288335A - Flow rate control device and flow rate control method for hydroelectric power station - Google Patents

Abstract

PURPOSE:To control the operating speed of a guide vane or nozzle, when a plurality of guide vanes or nozzles are switchingly used in Pelton wheel and cross flow hydraulic turbine, and prevent a flow rate change at switching transition. CONSTITUTION:When guide vanes 6a, 6b are controlled, it is detected by position switches 15a, 15b whether the guide vanes 6a, 6b are in switching transition. In the switching transition, an opening signal 30 from an opening indicator 19 is inputted to speed regulating devices 16a, 16b. In the speed regulating devices 16a, 16b, the upper limit values and lower limit values for speed signals 32a, 32b outputted from speed gains 23a, 23b are set by speed limiters 24a, 24b, and servo motors 12a, 12b are controlled at operating speeds ranging from the upper limit values to the lower limit values.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Pelton turbine, a cross flow turbine, etc., in which a plurality of flow rate adjusting mechanisms provided on the upstream side of the turbine are respectively switched to control the flow rate of a hydroelectric power station for adjusting the amount of water flowing into the turbine. The present invention relates to a control device and a flow rate control method.

[0002]

2. Description of the Related Art As a conventional flow control device, an actual fair 2-
As shown in Japanese Patent No. 38073, a cross flow
In the turbine, two guide vanes are installed on the upstream side of the turbine,
It has been proposed to adjust the amount of water flowing into the turbine by operating these two guide vanes.

In Japanese Patent Publication No. 59-12063, two large and small guide vanes are provided as guide vanes, and one or both of the two large and small guide vanes are switched to be used to flow into a water turbine. It has been proposed to adjust the water volume over a wide range.

Generally, there are a cross flow turbine and a Pelton turbine as a water turbine having two or more flow rate adjusting mechanisms, that is, guide vanes, and both of them are characterized by good variable flow characteristics. For example, in a cross-flow turbine, the guide vanes are set to 1 /
Divide into 3 and 2/3 length, or 1/2 length,
In the low flow rate partial load region, either one of the guide vanes is used for individual control, and in the vicinity of the maximum flow amount region, both guide vanes are controlled to have the same opening degree for high efficiency operation. Similarly, also in the Pelton turbine, it is general to perform high-efficiency operation in which the number of nozzles is switched and the partial load efficiency is improved. Hereinafter, the cross flow turbine will be described as an example.

FIG. 2 is a diagram showing a general water channel system of a hydraulic power plant using a cross flow turbine. Water flows into the upper water tank 8 through a water conduit (not shown), further enters the inlet pipe 5 through the hydraulic pipe 9, and flows into the runner 1. Rotatable guide vanes 6a and 6b are provided at the inlet of the runner 1 to adjust the amount of water flowing into the runner 1. The water that has passed through the runner 1 is guided to a water discharge channel 10 through a water discharge pipe 7.

As shown in FIG. 3, the structure of the cross-flow turbine is such that the runner 1 is housed in the casing 2, and the rotating shaft 3 of the runner 1 has a bearing frame 4 containing a seal and a bearing (not shown). It is rotatably supported by the casing 2 via. The entrance side of this casing 2, that is, the runner 1
An inlet pipe 5 is provided upstream of the inlet pipe 5, and the inlet pipe 5 is connected to the hydraulic line 9 described above. Split guide vanes 6a and 6b for adjusting the amount of water flowing into the water turbine are rotatably provided at the inlet end of the casing 2 on the outlet side of the inlet pipe 5.

Next, a highly efficient operation of the cross flow turbine will be described. FIG. 4 shows the above-mentioned guide vanes 6a and 6b.
It is a figure showing the efficiency of the cross flow turbine which divided into 1/3 vs. 2/3. As is clear from the figure, in the low flow rate region, the efficiency when operating with 1/3 guide vanes is higher than when using 2/3 guide vanes or 1/3 and 2/3 guide vanes simultaneously. can get. In the medium flow rate region, the highest efficiency is obtained when the 2/3 guide vanes are used, and the highest efficiency is obtained when both the 1/3 and 2/3 guide vanes are used near the maximum flow rate.

For this reason, the guide vanes 6a and 6b, which are generally flow rate adjusting mechanisms, are replaced by guide vanes as shown in FIG.
The operation is switched depending on the opening degree of the engine. In FIG.
In the low flow rate region, the flow rate flowing into the turbine is controlled using the 1/3 guide vane. At this time, the 2/3 guide vanes are in the fully closed position shown by point a in the figure. Next, when the 1/3 guide vane reaches the point b in the figure, the 1/3 guide vane is controlled to the point a in the figure, that is, the fully closed position, and the 2/3 guide vane is controlled to the point c in the figure. When the 2/3 guide vane reaches the point d in the figure, the control amount is switched so that the 1/3 guide vane and the 2/3 guide vane are located at the point e in the figure. On the contrary, during the closing operation, if the point f in the figure is reached, the 1/3 guide vane is fully closed and the 2/3 guide vane is controlled to the point g in the figure. Finally, when the point h in the figure is reached, the 2/3 guide vane is fully closed and 1/3
Control the guide vane to point i in the figure.

[0009]

However, in the above two conventional examples, the guide vane operating speed during the switching operation shown in FIG. 5 is uniquely determined by the opening deviation amount with respect to the target opening. Guide bases of different sizes
When the switching of the engine is in transition, for example, when switching from point b to point c in the figure, the flow rate is ideally constant at Q ₁ , but in reality the amount of water flowing into the runner increases due to the size ratio of the guide vanes. Then, the water level H1 of the upper water tank (see FIG. 2) decreases, and the turbine output increases too much. On the contrary, h shown in FIG.
When the point is switched to the point i, the amount of water flowing into the runner decreases, the water level H1 of the upper water tank rises, and the turbine output excessively decreases.

For this reason, considering only the water level H1 of the water tank, when the water level decreases due to an increase / decrease in the amount of water when the guide vanes are switched, air is sucked into the hydraulic pressure pipe line and the inside of the hydraulic pressure pipe line becomes negative pressure. There is a risk of crushing, and conversely, if the water level rises, there is a risk of water overflowing from the water tank.

Further, when switching the guide vanes, there is a problem that the control time constant of the control system for controlling the guide vanes must be constant in order to stably control the water turbine.

An object of the present invention is to prevent flow rate fluctuation during switching transition by controlling the operating speed of the guide vanes or nozzles when a plurality of provided guide vanes or nozzles are switched, and further It is an object of the present invention to provide a flow control device and a flow control method for a hydroelectric power plant, which can stabilize the water level of a water tank and the output of a water turbine and improve the control stability of the entire system.

[0013]

In order to achieve the above object, the present invention provides a plurality of flow rate adjusting means in the vicinity of a water turbine, and controls the plurality of flow rate adjusting means independently and by switching. In a flow control device of a hydraulic power plant that adjusts the amount of water flowing into the water turbine, a detection unit that detects a transitional transition time of the flow rate adjustment unit, and the flow rate adjustment unit when the detection transitional time is detected by the detection unit. An upper limit value and a lower limit value are set for the operating speed of the means, and a control means for controlling the flow rate adjusting means at an operating speed within the range of the upper limit value and the lower limit value is provided.

Further, according to the present invention, the above flow rate control device is installed in a cross flow turbine or a Pelton turbine.

Further, the present invention is a flow control method for a hydroelectric power plant, which adjusts the amount of water flowing into the water turbine by independently and switchingly controlling a plurality of flow control means provided near the water turbine, The upper limit value and the lower limit value are set to the operating speed of the flow rate adjusting unit during the transition of the switching of the flow rate adjusting unit, and the flow rate adjusting unit is controlled at the operating speed within the range of the upper limit value and the lower limit value.

[0016]

According to the above structure, the detecting means detects that the flow rate adjusting means is in transitional transition, and the control means which receives the detection signal sets the upper limit value and the lower limit value to the operating speed of the flow rate adjusting means. Then, the flow rate adjusting means is controlled at the operating speed within the range of the upper limit value and the lower limit value. As a result, the flow rate change due to the difference in the flow rate characteristics of the respective flow rate adjusting means is prevented, so that the flow rate during the switching transition can be made constant. As a result, the water level in the water tank can be kept constant at all times, and the output of the water turbine becomes almost constant, so that the control stability of the entire flow rate control system can be secured. Since the operating speed of the flow rate adjusting means is controlled by the control means, it is ensured that the control time constant when switching the flow rate adjusting means is constant.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings using a cross flow turbine as an example. The cross flow turbine has guide vanes 6a, which are divided as shown in FIG.
6b is fixed to the operation levers 11a and 11b, and the operation levers 11a and 11b are individually rotatably connected to the servo motors 12a and 12b. And the servo motor 1
Operation levers 11a, 11 by reciprocating 2a, 12b
By driving b, the guide vanes 6a and 6b rotate, and the amount of water flowing into the water turbine can be adjusted.

Generally, in a cross-flow turbine, after being paralleled to a system not shown, the amount of water flowing into the turbine, that is, the turbine output is adjusted by increasing or decreasing the water level H1 of the upper water tank 8 shown in FIG. Adjustment operation is performed. The water level information of the upper water tank 8 detected by the water level detector 20 is converted into an electric signal and taken into the opening degree indicator 19. The opening degree indicator 19 has a function of indicating the opening degree of the servo motors 12a and 12b based on the taken-in signal of the water level in the upper water tank, and the servo indicator via the changeover switches 17a and 17b.
Opening speed signal 30
Is output.

Servo motor speed adjusting devices 16a, 16b
The opening degree signal 30 taken in is added to the addition point 22a,
At 22b, it is added to the actual opening of the servo motor 31a, 31b, and as an opening deviation signal, the servo motor speed gain 23a,
23b is input. Here, the actual opening of the servo motor 31
Symbols a and 31b are signals that are detected by the opening degree detectors 14a and 14b attached to the servo motors 12a and 12b, converted into electric signals, and output. The servo motor speed gains 23a and 23b are respectively the servo motors 12a and 12b.
To output the speed signals 32a and 32b. The output speed signals 32a, 32b are limited by the speed limiters 24a, 24b and taken into the servo motor drive circuits 13a, 13b, and finally drive the servo motors 12a, 12b.

In the case of high efficiency operation, the servo motor 12a,
Servo motor position switch 15 for opening and closing the electric contact at a preset position by the reciprocating motion of 12b.
The servo motor switching position, that is, the switching transition state is detected by a and 15b, and a contact signal is sent to the operation control device 21. The operation control device 21 receives the input signal of the servo motor switching position and switches the switch 1
A switch switching signal is output to 7a or 17b.
Since the changeover switch 17a or 17b switches the position when the above-mentioned signal is input and switches to the direction of the fully closed signal 18, the minus signal of the above-mentioned opening deviation signal calculated by the speed adjusting devices 16a and 16b becomes large, The servo motors 12a and 12b are fully closed at a speed at which the speed limiters 24a and 24b are fully closed on the closing side. On the contrary, if the changeover switches 17a and 17b are switched to the opening signal 30 side, the plus signal of the opening deviation signal becomes large, so that the opening deviations of the servomotors 12a and 12b at the speed at which the opening side limit is full. Open operation until is 0. High-efficiency operation is performed by sequentially switching control using this control method.

Here, changeover switches 33 and 34 are connected to the speed limiter 24b, and the speed limiter 2
It is devised so that the value on the open side of 4b can be switched to the upper limit value 26 or 28 and the value on the close side can be switched to the lower limit value 27 or 29. The operation during high-efficiency operation will be described below assuming that the guide vane 6a is divided into 1/3 of the whole guide vane and the guide vane 6b is divided into 2/3 of the whole.

When the water level H1 of the upper water tank 8 is lower than the reference water level, the cross flow turbine is a guide vane 6a having a good low flow rate characteristic, and the amount of water flowing into the turbine is the water level detector 2
It is controlled via the opening indicator 19 according to the signal from 0. At this time, the changeover switch 17a is operated by the opening indicator 19
Since it is located on the side, the opening degree signal 30 is taken in by the speed adjusting device 16a. Then, the speed limiter 24a outputs the speed signal 32a whose upper and lower limit values are limited to the servo motor drive device 13a. The servo motor driving device 13a controls the position of the servo motor 12a and the amount of rotation of the guide vane 6a. On the other hand, since the changeover switch 17b is switched to the side of the fully closed signal 18,
The servo motor 12b is in the fully closed position and the guide vane 6b.
Is also in the fully closed position.

Next, when the water level H1 of the upper water tank 8 rises to reach the position where the guide vane 6b is switched to, that is, point b in FIG. 5, the position switch 15a of the servomotor 12a reaches the switching point. Contact information is sent to the operation control device 21. The operation control device 21 includes changeover switches 17a, 17
b, 33, 34 and the opening degree indicator 19, the changeover switch 17a is on the fully closed signal 18 side, the changeover switch 17b is on the opening degree signal 30 side, the changeover switch 33 is on the upper limit 28 side, The changeover switch 34 is switched to the lower limit 29 side. Further, the opening degree indicator 19 is switched to the opening degree to the point c position in FIG. 5 by a gain switching function (not shown). As a result, at the addition point 22a, the full-closed signal 0 and the actual opening degree of the servomotor 6b are matched, and at the addition point 22a, a signal of 0-31a is obtained. That is, it becomes a minus side opening signal corresponding to the G ₁ opening shown in FIG. 5, and this opening signal is the speed gain 23a.
And the servo motor drive device 13a by being sent to the servo motor drive device 13a via the speed limiter 24a.
3a starts the operation at the closing lower limit speed.

[0024] On the other hand, 'since the opening signal to the position is input, the summing point 22b G _1' from opening indicator 19 to the selector switch 17b G ₁ shown in FIG. 5 -0 signal or G ₁ of ′ It becomes a plus side opening degree signal for the opening degree, and the signal is taken in by the speed limiter 24b via the speed gain 23b. The changeover switch 3 is provided on the speed limiter 24b.
3, 34 are connected. These changeover switches 33 and 34 were calculated in advance from the upper limit 26 and lower limit 27 sides, respectively, from the relationship between the servo motor opening of the 1/3 guide vane and the 2/3 guide vane and the flow rate. The operation speed limit value at the time of switching is switched to the upper limit limit 28 side and the lower limit limit 29 side. Therefore, the servo motor 1
The servo motor 12 is driven through the servo motor driving device 13b so as to compensate for the same flow rate as the flow rate that decreases with the closing operation of 2a.
b is controlled, and it becomes possible to substantially suppress fluctuations in the flow rate flowing into the turbine.

The reason why the speed limiter function is provided only on the 2/3 guide vane side is that the 1/3 guide vane, which is smaller than the 2/3 guide vane, increases in speed at the time of load shedding and the hydraulic pressure pipe line. Even if it operates with the shortest closing time obtained from the limitation of the water pressure rise or the shortest opening time determined from the sudden load increase test, etc., in order to compensate the flow rate change per hour of the 1/3 guide vane, 2/3 Guide vanes and 1 /
This is because it is possible to compensate by limiting the opening / closing operation time of the 2/3 guide vane to half the operation time of the shortest opening / closing operation time of the 1/3 guide vane from the relationship of the size of the 3 guide vanes. . On the contrary, even if the speed limiter switching function is provided on the 1/3 guide vane side, the 2/3 guide vane is determined from the speed increase at the time of load shedding, like the 1/3 guide vane described above. Since it is impossible to compensate the flow rate change by operating for the shortest opening / closing operation time, it is practically impossible to compensate for the flow rate change by operating at a time faster than the shortest operating time.

When the water level in the upper water tank 8 further rises and reaches the point d in FIG. 5, the position switch 15b of the servo motor 12b sends a signal to the operation control device 21 that it is in the switching position. Changeover switch 17a from control device 21
And a switching signal is sent to the opening indicator 19, the opening indicator 19 switches from the position d to the position e in FIG. 5, and the changeover switch 17a is switched to the opening indicator 19 side. Therefore, service - Vomo - motor 6a operates in the shortest opening operation time by positive opening deviation signal G ₂ 'opening angle.

On the other hand, since the changeover signal is not input to the changeover switch 17b, the position of the switch remains the opening degree indicator 19 side. Therefore, the minus side operation signal corresponding to the G ₂ '-G ₂ opening degree deviation is generated. Occurs, which is the speed gain 23
It is input to the speed limiter 24b via b. At this time, since the changeover switch 34 connected to the speed limiter 24b is also switched to the lower limit 29 side, it is possible to substantially suppress the fluctuation of the amount of water flowing into the water turbine as described above.

Next, the water level in the clean water tank 8 drops and the servo
When the switch 12a reaches the point f in FIG. 5, the position thereof is sent to the operation control device 21 via the position switch 15a, and the operation control device 21 sends a changeover signal to the changeover switch 17a and the opening degree indicator 19 to send the servo signal. When the vomiter 12a is fully closed, the opening signal of the opening indicator 19 is switched to point g in FIG. 5, and the servomotor 12b opens at a speed that suppresses the flow rate change.

When the water level in the upper water tank 8 further drops and the servo motor 12b reaches the point h in FIG. 5, the position is sent to the operation control device 21 via the position switch 15b, and the operation control device 21 Since the changeover signals are sent to the changeover switches 17a and 17b and the opening degree indicator 19, the opening degree indicator 1
Will be switched opening signal 9 from the point h of FIG. 5 in the point i, Sa - Vomo - motor 12a operates in the shortest opening operation time to G ₄ 'opening, Sa - Vomo - motor 12b is flow rate change Similarly, the amount of water flowing into the turbine is kept almost constant because the valve is fully closed at a speed that suppresses

If some trouble occurs during the above operation and it is necessary to stop the water turbine suddenly, the operation control device 2
There is no problem if the logic for taking in accident information and incorporating the changeover switches 33 and 34 into the upper limit limit 26 and the lower limit limit 27, which are determined by the speed increase and the like, is incorporated in 1. Further, since only the upper and lower limit values are switched in this embodiment, the time constant of the control system shown in FIG. 1 is not changed and the stability of the control system is not impaired.

Next, the upper limit 28 and the lower limit 29 of FIG.
An embodiment of a method for continuously switching the will be described with reference to FIG. FIG. 6 is a diagram showing a speed adjusting portion of the servo motor 12b shown in FIG. 1. The speed limiter 24b is connected to the changeover switches 33 and 34 which are changed over by the changeover signal from the operation control device 21 as in FIG. Has been done.
Here, the flow rate characteristic 37 of the guide vane 6a shown in FIG.
Since it is easy to previously calculate the flow rate characteristic 38 of the guide vane 6b and the flow rate characteristics 37, 38
Can be stored as one control element in a control device (not shown). Similarly, the upper limit limit calculator 35 for the positive side of the flow rate deviation amount and the lower limit limit calculator 39 for the negative side of the flow rate deviation amount can be calculated and stored in advance as a relationship between the flow rate deviation and the limit value. In the following, the function of each part for continuously controlling the limit value in order to control the flow rate at the time of switching transition to be constant will be described.

The opening degree signals 31a and 31b of the guide vanes 6a and 6b are input to the flow rate characteristics 37 and 38 stored in the control device (not shown). Therefore, the outputs of the flow rate characteristics 37 and 38 are calculated as flow rates according to the guide vane opening. Next, the respective flow rates are added at the addition point 36, and are taken into the upper limit limit calculator 35 and the lower limit limit calculator 39 as a flow rate deviation signal. As a result, the limit value can be continuously changed according to each opening. Therefore, the guide base
It is possible to prevent a change in the flow rate flowing into the turbine during the transition of the switching of the turbine.

Next, FIG. 7 shows a case where upper and lower limit characteristics for the deviation amount of the water level of the water tank and the reference water level setting device are given instead of the upper and lower limit characteristics for each guide vane flow rate deviation explained in FIG. It is an example of. As shown in the figure, the setting signal from the reference water level setting device 40 is added to the detection signal from the water level detector 20 and added at the summing point 41, and is taken into the upper limit limit calculator 42 and the lower limit limit calculator 43 as a water level deviation signal. Be done. With the configuration of this embodiment as well, it is possible to prevent the change in the flow rate flowing into the water turbine during the switching transition, as in the case of FIG. 6.

Although not shown in the above embodiment, instead of the method of controlling the speed of the guide vanes, the opening signal of the guide vanes 6b during the switching transition is changed by means similar to those shown in FIGS. The same effect can be obtained by controlling.

Further, although the cross-flow turbine has been described in the above embodiment, it is needless to say that the present invention can be applied to other turbines such as Pelton turbine.

[0036]

As described above, according to the present invention,
During the transition transition of the flow rate adjusting means, it is possible to prevent the flow rate from changing due to the difference in the flow rate characteristics of the flow rate adjusting means and keep the flow rate constant. As a result, the water level in the water tank and the output of the generator can be maintained constant, and the control stability of the entire flow rate control system of the hydroelectric power plant can be improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a flow rate control device for a hydraulic power plant of the present invention.

FIG. 2 is a configuration diagram showing a water channel system of a cross flow turbine.

FIG. 3 is a structural diagram of a cross flow turbine.

FIG. 4 is an efficiency diagram of a cross flow turbine.

FIG. 5 is an explanatory diagram of high-efficiency operation of a cross flow turbine.

FIG. 6 is a structural diagram of a speed limiter switching device using a flow rate characteristic according to the present invention.

FIG. 7 is a structural diagram of a speed limiter switching device using water level deviation according to the present invention.

[Explanation of symbols]

 6a, 6b Guide vanes 12a, 12b Servo motors 14a, 14b Opening detectors 15a, 15b Position switches 16a, 16b Speed adjusting devices 17a, 17b, 33, 34 Changeover switch 18 Full closing signal 19 Opening instruction 20 Water level detector 21 Operation control device 22a, 22b, 36, 43 Addition point 23a, 23b Speed gain 24a, 24b Speed limiter 26, 28 Upper limit value 27, 29 Lower limit value 30 Opening signal 31a, 31b Servo-mo Opening signal 37,38 Flow rate characteristic 40 Reference water level setting device 35,42 Upper limit limit calculator 39,43 Lower limit limit calculator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Matsuzaki Inventor Kenichi Matsuzaki, 3-1-1, Saiwaicho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi factory

Claims (6)

[Claims] 1. A flow control system for a hydroelectric power plant, wherein a plurality of flow rate adjusting means is provided in the vicinity of a water turbine, and the plurality of flow rate adjusting means are independently and switched to control the flow rate of water flowing into the water turbine. In the apparatus, a detection unit that detects a transitional transition time of the flow rate adjusting unit and, when the transitional transition time is detected by the detection unit, sets an upper limit value and a lower limit value to an operating speed of the flow rate adjustment unit and sets an upper limit thereof. And a control unit for controlling the flow rate adjusting unit at an operating speed within a range between a lower limit value and a lower limit value, and a flow rate control device for a hydraulic power plant. 2. The flow rate control device for a hydroelectric power plant according to claim 1, wherein the upper limit value and the lower limit value are flow rates at the time of switching from flow rate characteristics of each of the flow rate adjusting means stored in advance in a host control apparatus. A flow rate control device for a hydroelectric power plant, wherein a change amount is calculated and calculated based on the flow rate change amount. 3. The flow rate control device for a hydraulic power plant according to claim 1, wherein the upper limit value and the lower limit value are calculated from a water level change amount of a water tank supplying water to the water turbine. Flow control device for hydroelectric power plant. 4. A cross flow turbine equipped with the flow rate control device according to claim 1. 5. A Pelton turbine equipped with the flow control device according to claim 1. 6. A flow control method for a hydroelectric power plant, which adjusts the amount of water flowing into the water turbine by independently and switchingly controlling a plurality of flow control means provided in the vicinity of the water turbine. The upper limit value and the lower limit value are set to the operating speed of the flow rate adjusting means during the transition of the switching, and the flow rate adjusting means is controlled at the operating speed within the range of the upper limit value and the lower limit value. Control method.