JPS6138169A - Operation of multi-stage hydraulic machine - Google Patents

Abstract

PURPOSE:To facilitate pushing down of water level by controlling such that when pushing down the water level, the movable guide vane at the highest pressure stage is fully closed while the movable guide vane at other stage is opened to feed the compressed air thereafter the movable guide vane at other stage is also fully closed. CONSTITUTION:When starting under generation mode, the upstage guide vane 7 is fully closed while the downstage guide vane 8 is set to predetermined opening thereafter starts to open air supply valves 9, 11 and guide vane leaked water discharge valves 19, 21. Then the compressed air is returned and fed into the vane flow path 5 and a draft tube 6 thus to lower the draft tube water level. Upon lowering to predetermined level, it is detected through a water level detector 18 to full open a switch 14 while to full close air supply valves 9, 11 then to full close the downstage guide vane 8. Thereafter, runner band discharge valves 22, 20 and an exhaust valve 13 are opened thus to control the water level in return vane flow path 5 through open/close operation of air supply valves 9, 11 which will respond to the outputs from the water level detectors 16, 17.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a multi-stage hydraulic machine, and in particular, to reducing the starting torque of a runner when starting a pump or operating a multi-stage hydraulic machine with a movable guide vane. This paper relates to an operation method for pushing down the water surface.

[Background of the invention]

Generally, in order to start or phase-adjust a large-capacity pump water turbine, etc., a motor-generator directly connected to the main shaft is started using a starting motor, but at this time the starting torque of the motor is In order to reduce this, so-called idling startup is performed.

In order to achieve this idle start, it is necessary to drain the water from the runner room. To drain water from this runner chamber, the highest pressure stage guide vane is fully opened, and the guide vanes of the other stages are kept open and the water surface is pushed down.
It is publicly known in No. This fully closes the large mouth valve or first stage guide vane provided at the casing inlet,
After blocking the pressure water from the penstock, the water surface around the pump runner is pushed down by compressed air, and the runner is exposed to the air to start the pump.

A conventional multi-stage hydraulic machine with movable guide vanes, such as a two-stage pump turbine, has a structure as shown in FIG. That is, 1 is the main shaft, 2 is the upper stage runner, 3 is the lower stage runner, 4 is the spiral casing, 5 is the return vane channel that communicates the upper and lower stages, 6 is the draft tube, 7 and 8 are the first stage and the second stage, respectively. This is a movable guide vane equipped with a

In such a two-stage pump-turbine, when starting the pump or performing phase-adjusted operation, even if the water surface pressing device of the conventional single-stage pump-turbine described above is applied as is, the resistance torque at startup can be sufficiently reduced. It is not possible to obtain the desired water surface depression state. This will be explained for the two-stage pump turbine shown in FIG.

That is, when pushing down the water surface, the upper guide vane 7 is fully closed, the lower guide vane 8 is fully opened, and compressed air is forcibly supplied to the back pressure chamber of the upper runner 2. Then, the water around the runner 2 is pushed through the return vane channel 5 by the compressed air, and is successively pushed into the runner chamber from the final stage guide vane 8, resulting in a state where the water surface is pushed down as shown in Fig. 2. It is.

In the case of a pump-turbine, it is necessary to maintain the water surface in a depressed state under the rotation of the pump, but the above-mentioned known examples have the following problems. That is, in the pump mode, the runner uses centrifugal force to blow away the cooling water supplied to the runner and the water falling from the upper stage thinner chamber while the water surface is being pressed down, and the i function works to carry this water to the high pressure stage. This water must ultimately be discharged to the draft tube side, but the above phenomenon is exactly a backflow phenomenon, which is truly inconvenient and has an essential defect.

However, considering that the purpose of pushing down the water surface is to reduce the starting torque of the runners, it is necessary to remove the water around the runners at each stage and eliminate the water bodies in the return vane flow path. That's not true.

Therefore, a multi-stage hydraulic machine was invented, as shown in Japanese Patent Publication No. 47-38336, in which a bypass pipe was provided which communicated from the return passage to the draft tube.

This invention requires a bypass pipe with a large diameter and an automatic valve on this pipe, and although the return passage is originally a narrow place, the above-mentioned bypass pipe and automatic valve are required. In addition, if the bypass line valve were to malfunction (for example, if it opened during normal turbine or pump operation), water leakage would cause a loss of turbine or pump efficiency. However, unlike when the water surface is pressed down, the pressure in the return passage becomes high, which has the disadvantage that the bypass pipe valve may be accompanied by vibration.

[Purpose of the invention]

An object of the present invention is to provide a method of operating a multi-stage hydraulic machine that can reliably push down the water surface with a simple structure.

[Summary of the invention]

The present invention fully closes the upper guide vane when pressing down on the water surface, opens the lower guide vane slightly to achieve a predetermined water surface pressing, and then closes the lower guide vane to take advantage of return vane flow channel water level control. After that, the water level control in the upper runner room (i.e., the return vane flow path) and the water level in the lower runner room (i.e., the draft tube) are performed separately, and the downward air pressure in the upper runner room is made higher than the outer peripheral water pressure in the lower runner. The system is designed so that water falling from the upper runner chamber and cooling water supplied to the lower runner are smoothly discharged into the draft tube through the lower runner chamber without accumulating in the return vane flow path. The idea is to be able to lower the water level in the event of a disaster.

[Embodiments of the invention]

Examples of the present invention will be described below.

FIG. 1 shows an embodiment of the invention.

In the figure, the same reference numerals as in the embodiment shown in FIG. 4 indicate the same parts and the same functions. In the figure, compressed air is supplied to the upper stage runner 2 from an air supply valve 9 via a check valve 10. Further, compressed air is supplied to the lower runner 3 from an air supply valve 11 via a check valve 12.

Further, the spiral casing 4 is provided with an exhaust valve 13.

On the other hand, in order to detect three different water levels in the return blade flow path 5, a return blade flow path water level first stage detector 15, a return blade flow path water level second stage detector 16, and a return blade flow path water level third stage detector 15 are installed. Stage detectors 17 are provided, each of which is connected to a switch 14 that is connected to the draft tube 6.

Nine, the draft tube 6 is equipped with a draft tube water level detector 1 for detecting the water level inside the draft tube 6.
8 is provided.

Further, a cut vane water leakage drain valve 19 is provided near the movable guide vane 7 in order to drain water leaking through the gap between the movable guide vanes 7 into the draft tube 6. A runner band drain valve 20 is provided near the upper runner 2 to drain water leaking from the runner band to the draft tube 6. Further, the lower movable page 78 and the lower runner 3 are also provided with a guide vane water leakage drain valve 21 and a runner band drain valve 22, respectively.

Since the device is constructed in this way, the operation in the power generation mode will first be explained using the time chart of FIG. 2. In other words, during the power generation operation shown in Fig. 2 (4), 10
Sometimes, as shown in Fig. 2 (6), the upper movable guide vane 7
At the same time, as shown in FIG. 2, the lower movable guide vane 8 is operated in the closing direction. When the lower movable guide vane 8 reaches a predetermined opening degree (time ts), it stops operating as shown in FIG. 2 (2). When the upper movable guide vane 7 is fully closed (time t2), the water leakage replenishment valve (not shown) as shown in FIG. Then, the runner seal water supply valve (not shown) begins to open as shown in FIG. When the water supply valve 9.11 is fully opened, compressed air is supplied into the return vane flow path 5 and draft tube 6, and the water level that has been clogged up to the upper movable guide vane 7 is pushed down by the compressed air. As shown in Fig. 2 (■), the water level in the return vane flow path decreases, and thereafter, as shown in Fig. 2 0, the draft tube water level decreases. When the draft tube water level falls to L3 (at time ts) as shown in FIG. 20, the switch 14 begins to open as shown in FIG. 20. At the same time, the air supply valve 9.11 begins to close, as shown in FIGS. When this switch 14 is fully opened and the air supply valves 9 and 11 are fully closed (time t4), the lower movable guide vane 8 starts to operate from a predetermined -displacement position in the fully closed direction as shown in the second side cut. do. At the same time, the runner band drain valve 22 as shown in FIG. 2(B) and the runner band drain valve 20 as shown in FIG. After the movable guide vane 8 is fully closed, detection is performed by the return vane flow path water level second stage detector 16 shown in the second face cut and the return vane flow path water level third stage detector 17 shown in FIG. 2(I). Controlled by value. That is, as shown in FIG. 2G), when the draft tube water level is detected as L by the draft tube water level detector 18,
When the air supply valve 11 is opened as shown in FIG. 2G, the water level of the return vane flow path fluctuates as shown in the second diagram, and as shown in the second section,
When the third stage water level detector 17 of the return vane flow path detects the water level, the operation of opening the air supply valve 9 is repeated as shown in FIG.

Next, the operation in the pump mode will be explained using the time chart of FIG. That is, as shown in FIG. 3 (4), when the main shaft 1 is not rotating at all, the lower movable guide vane 8 is operated to a predetermined opening degree as shown in the third figure at the time of to. At the same time, as shown in FIG. 30, a water leakage replenishment valve (not shown), an air supply valve 9 as shown in FIG. 3(G), and a runner seal water supply valve as shown in FIG. 3(G), As shown in Figure 3 Q[F], the guide vane water leakage drain valve 19, the runner band drain valve 20, the guide vane water leakage drain valve 21, the runner band drain valve 22
open. Thereafter, as shown in FIG. 30, the draft tube water level reaches the position where Ll is detected by the draft tube water level detector 18, and the main shaft 1 begins to rotate as shown in FIG. 3(4). Further, as shown in the third direction, when the draft tube water level reaches the position Ls, the lower movable guide vane 8 is closed as shown in FIG.
Fully open the switch 14 as shown in . This allows the third
As shown in Figure α) Gl), the return blade flow path water level third stage detector 17 and the return blade flow path water level second stage detector 16 are ON and OFF.
F works. By detecting the draft tube water level La shown in FIG. 3 0, the water supply valve 1 as shown in FIG.
1 is controlled, and the water supply valve 9 is controlled as shown in FIG. 3 (G) by detecting the water level of the return vane flow path as shown in FIG. Note that the exhaust valve 13 is kept fully closed as shown in the third direction.

Therefore, according to this embodiment, there is no need to provide a bypass pipe communicating from the return vane flow path to the draft tube, so the structure is extremely simple.

Furthermore, according to this embodiment, the efficiency of the water turbine or pump is not lost.

〔Effect of the invention〕

As explained above, according to the present invention, the water surface can be reliably pushed down with a simple structure.

[Brief explanation of drawings]

Fig. 1 is a schematic structural diagram showing an embodiment of the present invention, Fig. 2 is a time chart showing a method of moving from water turbine mode to phase adjustment operation according to the present invention, and Fig. 3 is a time chart when starting the pump according to the present invention. , FIG. 4 is a vertical cross-sectional view showing a schematic structure of a two-stage pump turbine, and FIG. 5 is a schematic structural view showing a state in which the water surface is pressed down when the pump is started by a conventional device. l...Main shaft, 2...Upper runner, 3...Lower runner, Taku 2 figure 13 stomach

Claims (1)

[Claims] 1. A movable guide vane is provided at each stage so that compressed air can be individually supplied to the runner chamber of each stage, and the water surface of the runner chamber of each stage can be individually detected. In a multi-stage hydraulic machine configured as shown in FIG. After detecting that water has been removed from the runner chambers of multiple stages (including the lowest pressure stage), the movable guide vanes of all stages other than the highest pressure stage, which had been open until now, are also fully closed, and after that, the water level of each runner room is A method of operating a multi-stage hydraulic machine that individually detects water levels and replenishes compressed air accordingly to control individual water levels. 2. A multi-stage hydraulic machine that has movable guide vanes at each stage and is configured so that compressed air can be supplied individually to the runner chambers of each stage, and the water surface of the runner chambers of each stage can be individually detected. When pressing down the water surface, the highest pressure stage guide vanes are fully closed, and the guide vanes of the other stages are slightly closed, and the pressing is completed sequentially from the highest pressure stage runner chamber to the small low pressure stage runner chamber. When the pressing of the high pressure stage runner chamber is completed, the second stage guide vane is fully closed, taking advantage of the individual water level control of the highest pressure stage runner chamber, and in the same manner, when the pressing of each runner chamber is completed, the next stage guide vane is fully closed. A method of operating a multi-stage hydraulic machine that takes advantage of individual water level control in the runner room.