JPH02267367A - Water surface depression device for pump hydraulic turbine - Google Patents

Abstract

PURPOSE:To prevent high pressure air from leaking to a draft tube lower stream side at the time of racing of a runner, by providing a water surface detecting tank aside in relation to the draft tube, and also arranging, on this tank and in upper and lower direction, a plurality of supply valve opening/closing electrode switches, for opening/closing a high pressure air supply valve after detecting water level inside the draft tube. CONSTITUTION:A pump hydraulic turbine is provided with a spiral casing 1, the guide vane 2 for adjusting flow rate which is arranged in this casing 1, a runner 4 arranged in a runner chamber 3, and a draft tube 5 connected to the lower end of the runner chamber 3. In this occasion, a water level detecting tank 10 communicating to the draft tube 5 through a communication pipe is provided aside. A water level alarm electrode switch 11a, electrode switches 11d, 11e for opening/closing a high pressure air supply valve 14 for racing of the runner 4 in the pump direction, and electromagnetic switches 11f, 11g for opening/closing the high pressure air supply valve 14 at the time of racing of the runner 4 in the hydraulic turbine direction are mounted on the side of this tank 10 successively from its upper part. And when the electrode switch 11d turns on at the time of racing of the runner 4 in the pump direction, the high pressure air supply valve 14 is opened after lapse of a limited time.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a water level pressing method that forcibly lowers the water level in the suction pipe of a pump-turbine to cause the runner to idle. Regarding equipment.

(Conventional technology) When starting a large capacity pump-turbine, or when using a large-capacity pump-turbine to perform phase adjustment operation to stabilize the power system, a runner is placed around the runner. Generally, the guide vanes for adjusting the flow rate are fully closed, the water in the runner chamber is drained by supplying high pressure air to the flow path in the runner chamber, and the runner is operated in the air to reduce the runner driving torque. It is being said.

In this case, the water in the casing enters the runner chamber through the small gap between the completely closed guide vanes, and due to the centrifugal action of the rotating runner, this water sticks to the outer periphery of the runner chamber. Subject to stirring action. As a result, the loss energy increases and the runner drive becomes large, and a phase heat amount is generated, which heats the runner and the surrounding runner chamber, causing the temperature to rise over time, and due to thermal expansion. There was a problem that it deformed.

In order to solve this problem, a system has been proposed in which control piping is provided on the outer circumferential side of the runner to control drainage. This will be explained with reference to FIG.

The pump turbine consists of a spiral casing 1 and a casing 1.
A guide vane 2 for flow rate adjustment arranged at the inner peripheral opening of the runner, a rotatable runner 4 disposed inside the runner chamber 3 with the outer peripheral end opened to the guide vane 2, and a runner 4 communicating with the runner 4. It has a suction pipe 5 connected to the lower end. It also includes a high-pressure air supply pipe 13 for supplying high-pressure air to the runner chamber 3 when pushing down the water surface, and a high-pressure air supply valve 14 disposed in the middle thereof. And runner room 3
Control piping 6°7 is provided between the outer peripheral end of the runner chamber 3 and the suction pipe 5, and between the lower part of the runner chamber 3 and the suction pipe 5, and control valves 8, 7 are provided inside the control pipes 6 and 7, respectively. 9 is interposed, so that the water that has entered the runner chamber 3 is forced to flow out into the suction pipe 5 through the control pipes 6 and 7. In addition, a water level detection tank 10 composed of a communication pipe connected to the suction pipe 5 is provided in parallel with the suction pipe 5, and a warning water level electrode switch lla is installed on the side of the detection tank 10 from above.
, the high-pressure air supply valve 14, the opening electrode switch 11b, the high-pressure air supply valve 14, and the opening electrode switch llc are arranged in this order. Since there is a very small amount of air leaking from the high-pressure air seal, etc., when the water level in the suction pipe 5 reaches the installation position of the supply valve closing electrode switch Ilb, this switch Ilb is activated to supply high-pressure air to the runner. The water level is supplied to the flow path in the chamber 3, and the water level is controlled by the electrode switch l for opening and closing the supply valve.
Push down to the LC installation position. After pushing down the water surface 20 with the guide vane 2 fully closed, the runner 4
When running in the air, the water surface 20 changes as the runner 4 rotates.
sways. When this oscillating water surface 20 reaches the runner, the water sticks to the outer periphery of the runner chamber 3 due to the centrifugal action of the runner 4. Since the amount of this water is so large, the control piping 6.7 provided on the outer periphery of the runner 4 is not completely drained, resulting in problems such as thermal expansion and deformation similar to those described above. Therefore, when the water level in the suction pipe 5 reaches the installation position of the warning water level electrode switch lla, control is performed to stop the main engine. In addition, in order to maintain the water level in the suction pipe 5 at an appropriate level, this water level is
When the water surface 20 reaches the installation position of the supply valve opening/closing electrode switch llc, high-pressure air is supplied to control the water surface 20 to be pushed down to the installation position of the supply valve opening/closing electrode switch llc. , 52-1359
Publication No. 43).

(Problems to be Solved by the Invention) In the conventional example described above, the level at which the water surface of the suction pipe is pushed down is always constant regardless of whether the runner rotates in the direction of the pump or in the direction of the water wheel. However, in large-capacity pump-turbines, especially high-speed pump-turbines, the runner 4
The pressure state at the outer circumference of the runner 4 is different between rotation in the pump direction and rotation in the water wheel direction. That is, when the runner 4 rotates in the pump direction, the pressure at the outer circumference of the bell runner 4 becomes higher than when the runner 4 rotates in the water wheel direction. Therefore, high-pressure air is discharged like a jet into the suction pipe 5 through the control pipe 6°7 so as to push out the water stuck to the outer periphery of the runner chamber 3. At this time, the water surface 20 of the suction pipe 5 is oscillating, and this oscillating water surface acts to push the jet toward the downstream side of the suction pipe 5 near the bent portion of the suction pipe 5. For this reason, there was a problem in that high-pressure air leaked to the downstream side of the suction pipe 5, as shown in FIG.

Here, in order to prevent this leakage, it is conceivable to lengthen the vertical part of the suction pipe 5 and to make the distance between the oscillating water surface and the bent part of the suction pipe 5 sufficiently large to prevent leakage. However, in this case, the amount of civil engineering excavation required during the installation of the pump-turbine has the disadvantage of increasing costs and making the installation work quite troublesome.

Therefore, as one method for dealing with this problem of high-pressure air leakage, a method as shown in FIG. 8 has been adopted. That is, as in the conventional example, the water level detection tank 10 is constructed of a communication pipe that is parallel to the suction pipe 5 and communicates with the suction pipe 5.
and supply valve opening/closing electrode switches lld, lle, ll for opening and closing the high-pressure air supply valve 14 which detects the water level in the suction pipe 5 in the detection tank 10.
f and l1g are arranged in order in the vertical direction, and among these, the electrode switches lid and lie located on the upper side are used for opening and opening when the pump is idling, respectively, and the electrode switches llf and l1g located on the lower side are used for opening and opening, respectively, when the pump is idling. It is configured to operate as an opening and opening when the direction is idling. According to this, the electrode switch lie for closing the high-pressure air supply valve when the runner 4 is idling in the pump direction is set to a higher level than the electrode switch l1g for closing the high-pressure air supply valve when the runner 4 is idling in the water turbine direction. The water level 20 in the suction pipe 5 is maintained at a higher water level when the pump is idling in the direction of the pump than when it is idling in the water wheel direction. Therefore, the distance between the oscillating water surface 20 and the bent portion of the suction pipe 5 can be made larger when the pump is idling in the pump direction than when it is idling in the water wheel direction. Therefore, the control piping 6, 7
High-pressure air suction pipe 5 that is discharged more like a jet
The leakage to the downstream side can be reduced by the distance from the swinging water surface 20, and this leakage can be further suppressed. According to this example, for example, the high-pressure air supply valve 14 is opened when the water level in the suction pipe 5 when the pump is idling is first detected by the high-pressure air supply valve opening electrode switch lid. Become.

On the other hand, as shown in FIG. 9, the mode of rise in the water level 20 in the oscillating suction pipe 5 is one waveform state with a high water level point A and a low water level point B. This is a mode that gradually increases over time.

Here, the timing at which the high-pressure air is supplied is such that the supplied high-pressure air does not flow to the downstream side of the suction pipe 5 at both the point A where the water level is high and the point B where the water level is low on the oscillating water surface 20. There is no problem if the water level is at a stable distance, but as mentioned above, even if the water level is at an unstable distance, the point A where the water level is high in one waveform of the oscillating water surface is high pressure. Electrode switch for opening air supply valve li
Even if the level d is reached, the high-pressure air supply valve 14 will be opened, and high-pressure air will be supplied. Therefore, even if high-pressure air is supplied in this state, the low water level point B in one waveform will be below the stable water level, so if this part comes near the bend of the suction pipe 5, it will be the same as in the conventional example. Another problem is that high-pressure air leaks to the downstream side of the suction pipe 5.

In view of the above, an object of the present invention is to provide a relatively simple device that prevents leakage of the high-pressure air to the downstream side of the suction pipe as much as possible.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention supplies high-pressure air into the suction pipe of a pump-turbine through a high-pressure air supply valve, thereby lowering the water level in the suction pipe and increasing the runner height. In the device for pushing down the water surface of the pump, which enables idling operation, a water level detection tank is installed in communication with the above-mentioned suction pipe, and the water level in the suction pipe is detected by the water level detection tank to open and close the high-pressure air supply valve. A plurality of supply valve opening/closing electrode switches are arranged vertically, and when the supply valve opening/closing electrode switch located above is idling in the direction of the runner's pump, the supply valve opening/closing electrode switch located below is arranged in the direction of the runner's water turbine. The high-pressure air supply valve is configured to be activated when the pump is idling, and when the supply valve opening electrode switch that is activated when the pump direction is idling detects a rise in water level, the high-pressure air supply valve is opened after a certain period of time has elapsed. This is what I did.

(Function) According to the present invention, since the electrode switch for opening and closing the high-pressure air supply valve when the runner is idling in the pump direction is set to a higher level than the electrode switch for opening and closing the high-pressure air supply valve when the runner is idling in the water turbine direction, The water level of the suction pipe is maintained at a higher water level when the pump is idling in the direction of the pump than when it is idling in the water turbine direction. Therefore, the distance between the oscillating water surface and the bent portion of the suction pipe can be made larger when the pump is idling in the pump direction than when it is idling in the water wheel direction.

In addition, the electrode switch for opening the high-pressure air supply valve when the pump is idling is installed after a certain period of time after detecting a rise in the water level.
Since the high-pressure air supply valve functions to open, prevention of high-pressure air leakage can be more reliably improved.

(Embodiment) Figures 1 to 6 show an embodiment of a pump-turbine according to the present invention, in which a spiral casing 1 and a guide for adjusting the flow rate arranged at the inner peripheral opening of the casing 1 are shown. vane 2
A runner 4 is rotatable and is disposed inside a runner chamber 3 with its outer peripheral end opened to the guide vane 2, and a suction pipe 5 is connected to the lower end of the runner 4 and communicated with the runner 4.

Further, a high-pressure air supply pipe 13 for supplying high-pressure air to the runner chamber 3 when pushing down the water surface, and a high-pressure air supply valve 14 disposed in the middle thereof are provided.

A control valve 8 is provided inside each between the outer peripheral end of the runner chamber 3 and the suction pipe 5 and between the lower part of the runner chamber 3 and the suction pipe 5.
, 9 are disposed, and a water level detection tank 10 is also provided in parallel with the suction pipe 5 and constituted by a communication pipe communicating therewith.

On the side of the detection tank 10, from above, there is a warning water level electrode switch lla, and a high pressure air supply valve 1 for when the pump direction is idling.
4. An electrode switch 11d' for opening, an electrode switch lie for closing the high-pressure air supply valve, an electrode switch Iff for opening the high-pressure air supply valve when idling in the water turbine direction, and an electrode switch L1g for closing the high-pressure air supply valve. They are arranged sequentially. Further, the electrode switch lid' for opening the high-pressure air supply valve when the pump direction is idling is attached with a timer device 12 having a delay function so that the high-pressure air supply valve is opened after a certain period of time has passed after the detection of the water level. .

When the runner 4 is idling in the direction of the water wheel, as shown in Fig. 3, when the water level in the suction pipe 5 reaches the installation position of this supply valve opening electrode switch Ilf, it is activated to supply high pressure air to the runner chamber. When the water level in the suction pipe 5 reaches the installation position of the supply valve closing electrode switch l1g, the switch is actuated to stop the supply of high-pressure air. When the pump direction is idling, the fourth
As shown in the figure, when the water level in the suction pipe 5 reaches the installation position of this supply valve opening electrode switch 11d', it is activated to supply high pressure air to the flow path section of the runner chamber 3, and the suction pipe When the water level of 5 is reached, this supply valve closes with an electrode switch.
The basic structure is such that when the air conditioner reaches the installation position, it is activated and the supply of high-pressure air is stopped. As a result, the water surface of the suction pipe 5 is.

Since the water level is maintained at a higher level when the pump is idling in the direction of the water wheel than when it is idling in the water wheel direction, the distance between the oscillating water surface 20 and the bent part of the suction pipe 5 is set at a higher level when the pump is idling in the direction of the water wheel than when it is idling in the water wheel direction. In addition, as shown in FIGS. 5 and 6, in the high-pressure air supply valve opening/closing electrode switch 11d' for when the pump is idling, the switch 11d' is used after a certain period of time has elapsed after the water level rise is first detected, that is, when the pump is idling. After both the high and low water levels of the moving water surface rise to a water level that has a stable distance from which high pressure air does not flow downstream of the suction pipe 5, the supply valve 14 is opened to supply high pressure air. Therefore, even if the high-pressure air is discharged like a jet through the control pipes 6 and 7 into the suction pipe 5 at this point, the high and low water level parts of the oscillating water surface 20 inside the suction pipe 5 will be Since both water levels have reached a stable water level, the problem of high pressure air leaking to the downstream side of the suction pipe 5 can be improved.

〔Effect of the invention〕

Since the present invention has the above-mentioned configuration, it is possible to suppress leakage of high-pressure air for pushing down the water level of the suction pipe to the downstream side of the suction pipe during idle running of the runner with a relatively simple device. This has the effect of allowing the runner to perform stable idling operation without leakage of high-pressure air.

[Brief explanation of drawings]

Figures 1 to 6 schematically show a pump-turbine equipped with an embodiment of the present invention, with Figure 1 being a longitudinal sectional front view thereof, Figure 2 being a front view showing a water level detection tank, and Figure 3 being a direction towards the water turbine. FIG. 4 is a diagram equivalent to FIG. 1 showing the state when the pump is idling, FIG. 4 is a diagram equivalent to FIG. 1 showing the state when the pump is idling, and FIG. 5 is a diagram equivalent to FIG. Fig. 6 is the first diagram showing the state when high pressure air is supplied when the pump is idling in the direction of the pump.
Figure 7 is a diagram equivalent to Figure 1 of the conventional example, Figure 8 is a diagram equivalent to Figure 1 of an improved example of the conventional example, and Figure 9 shows the rising trend of the water level of the oscillating water surface in the suction pipe. FIG. 1...Casing 2...Guide vane 3.
...Runner room 4...Runner 5...Suction pipe 6,7...Control piping 8.9...Control valve IO...Water level detection tank 11a...Warning water level electrode switch 11d'・・Electrode switch for opening the supply valve when the pump is idling in the pump direction ・・Electrode switch for closing the supply valve 11f ・・・Electrode switch for opening the supply valve when the pump is idling in the water turbine direction 11g・・・Electrode switch for closing the supply valve 12 ... Timer device 13 ... High-pressure air supply pipe 14 ... High-pressure air supply valve 20 ... Mizu surface agent Patent attorney Nori Chika Ken Yudo Daishimaru Ken Figure Figure Figure

Claims (1)

[Claims] A water level detection tank is used in a pump-turbine water level lowering device that supplies high-pressure air into the suction pipe of a pump-turbine through a high-pressure air supply valve, thereby lowering the water level in the suction pipe and allowing the runner to idle. A plurality of supply valve opening/closing electrode switches are provided in communication with the suction pipe and arranged in the vertical direction in the water level detection tank for detecting the water level in the suction pipe and opening/closing the high pressure air supply valve;
The electrode switch for opening and closing the supply valve located above is configured to operate when the runner is idling in the direction of the pump, and the electrode switch for opening and closing the supply valve located below is configured to operate when the runner is idling in the direction of the water wheel. A device for pushing down the water surface of a pump-turbine, characterized in that the high-pressure air supply valve is opened after a certain period of time when a rise in water level is detected by an electrode switch for opening the supply valve, which is activated at the same time.