JPS6056915B2 - Operation control method for multi-stage hydraulic machinery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the operation of a multi-stage hydraulic machine, and in particular, the flow paths of each stage from the lowest pressure stage to the highest pressure stage are connected by return passages, and the highest pressure The present invention relates to an operation control method for switching from idling operation in the direction of a water turbine or pump to power generation operation or pumping operation, respectively, in a multi-stage hydraulic machine having movable guide vanes only in the stepped portions.

In general, in hydraulic machinery, in order to reduce the runner drive torque during water turbine harmonized operation or pump start-up operation, the runners are operated in the air by pushing down the water in the flow path using high-pressure air supply, and then the flow path is ``After exhausting the residual air and filling the channel with water, we shift to the required water turbine power generation operation or pump pumping operation.

Among hydraulic machines, runner chambers of each stage are connected by return passages, and in the case of multi-stage hydraulic machines with complicated flow path shapes, various exhaust gases are used when switching from idling operation to power generation operation or pumping operation. tend to cause problems.

Multi-stage hydraulic machines that have a movable guide vane only in the highest pressure stage are equipped with a movable guide vane or the like in the middle of the flow path from the runner chamber of the highest pressure stage to the runner chamber of the lowest pressure stage. Since there is no structure that can control the flow, the flow path is always in communication, and fluid phenomena are immediately transmitted between the runner chambers.

In a multi-stage hydraulic machine where the runner chambers of each stage are always in communication via return passages, compressed air can be used to push down the water in the runner chambers by opening the upper cover of the runner chamber of the highest pressure stage. A conceivable operating method is to supply air and push the water in the return passage down to the suction pipe for idling operation, and then, when transitioning to power generation operation or pumping operation, to exhaust air from the upper cover of the runner chamber at the highest pressure stage. However, as mentioned above, when trying to fill the water by exhausting the compressed air supplied to the flow path of the runner chamber of each stage from the runner chamber of the highest pressure stage, the compressed air enters the runner chamber of the lowest pressure stage. Because high-pressure flowing water and compressed air collide in the flow path around the outer periphery of the runner in the lowest pressure stage, a mass of mixed phase water and air reciprocates between each stage. In other words, the multiphase state of water and air in the flow path due to the pressure sources of the runners in each stage interferes violently, causing exhaust congestion, resulting in vibrations, noise, abnormal water pressure fluctuations, etc., and smooth exhaust water filling. difficult to do. However, in this way, only the highest pressure stage is movable. Multi-stage hydraulic machines with devanes themselves are technically unexplored in many fields, and a simple and accurate operation control method has not yet been proposed when switching from idling operation to required power generation operation or pumping operation. That is the reality.

Therefore, an object of the present invention is to provide a multi-stage hydraulic machine that is capable of reliably discharging air in a flow path step by step from a low-pressure stage to a high-pressure stage when transitioning from idling operation to power generation operation or pumping operation. An object of the present invention is to provide an operation control method.

According to the present invention, the above object is achieved by connecting the runner chambers of each step from the lowest pressure step to the highest pressure step by a return passage, and providing a movable guide vane only in the highest pressure step. In the operation control method of a multi-stage hydraulic machine, the movable guide vane is fully closed, the water in the runner chamber is pushed down to the bottom of the runner chamber at the lowest pressure stage by air supply, and the runners at each stage are idled toward the water wheel or pump. When transitioning from an operating state to power generation operation or pumping operation, first, while exhausting only the compressed air in the runner chamber of the lowest pressure stage, the water in the suction pipe is charged into the lowest pressure stage runner chamber, and then the water in the lowest pressure stage runner chamber is filled with water. When the boundary between the air phase and the water-filled phase from the low-pressure stage side reaches approximately the center of the turning section of the return passage, exhausting of the compressed air in the adjacent high-pressure stage runner chamber begins, thereby causing the low-pressure stage runner to The pressurized water in the chamber is guided into the runner chamber of the next stage through the return passage, and each stage from the lowest pressure stage to the highest pressure stage is sequentially evacuated and filled with water, until the highest pressure stage runner chamber is underwater. When the specified pressure or water level in the cut-off state is reached, the exhaust from the runner chambers of each stage is stopped, and the movable guide vanes are then opened to a predetermined opening degree to shift to power generation or pumping operation. will be achieved.

According to the present invention, the runner chamber of the lowest pressure stage section is first evacuated, and the filled water in the low pressure stage runner chamber is introduced into the return passage while compressing the air in the return passage, and is introduced from the low pressure stage side. Since the exhaust from the high-pressure stage runner chamber side is started when the boundary between the water-filled phase of The air phase separates the runner, which is a pressurization source, so that the air in the flow path can be smoothly and reliably discharged while avoiding a rapid flow state due to a mixed phase of water and air.

Embodiments of the method for controlling the operation of a multi-stage hydraulic machine according to the present invention will be described below with reference to the drawings.

To facilitate understanding of the present invention, FIG. 1 shows a Francis-type two-stage pump-turbine as an example of a multi-stage hydraulic machine, in which a single main shaft 1 has a high-pressure stage runner 2 and A low pressure stage runner 3 is fixed at a distance in the axial direction.

The high pressure stage runner 2 is surrounded by an upper cover 4 and a lower cover 5, while the low pressure stage runner 3 is surrounded by an upper cover 6 and a lower cover 7, forming a high pressure stage runner chamber 8 and a low pressure stage runner chamber 9. There is. The high pressure stage runner chamber 8 and the low pressure stage runner chamber 9 are connected by a return passage 10, and a return vane 11 and a stay vane 12 are provided on the passage. Further, a spiral casing 13 is provided outside the high pressure stage runner chamber 8.
The whirlpool chamber 14 and the high-pressure stage runner chamber 8 are communicated with each other, and the inlet of the hollow chamber is connected to a penstock via an inlet valve.

Furthermore, a movable guide vane 15 is provided on the outside of the high-pressure stage runner 2, and the opening degree of the guide vane can be adjusted by a guide vane operating mechanism (not shown).

Note that an elbow-shaped suction pipe 1 is provided in the low-pressure stage runner chamber 9.
6 is connected, and its downstream side communicates with the drainage channel.

An exhaust pipe 17 is connected to the upper cover 4 of the high pressure stage runner chamber 8, while an exhaust pipe 18 is connected to the upper cover 6 of the low pressure stage runner chamber 9, and exhaust valves 19 and 20 are installed on each pipe. is incorporated.

When operating the two-stage pump turbine configured as described above, pressure water from the penstock is transferred to the spiral casing 13.
The water flow flows into the swirl chamber 14, passes through the movable guide vane 15 of the high pressure stage section, passes through the return passage 10, flows through the low pressure stage runner 3, and then flows into the suction pipe 16.

On the other hand, during pump operation in which the runner rotates in the opposite direction at the same rotational speed as the water turbine, the water flow pumped up by the low-pressure stage runner 3 passes from the suction pipe 16 to the penstock through the reverse route of the water turbine operation described above. It will be distributed to.

Next, a description will be given of an operation control method when the present invention is applied to the above-mentioned two-stage pump water turbine to cause it to idle in the direction of the water wheel or pump, and then to shift from that state to power generation operation or pumping operation.

After fully closing the movable guide vane 15 prior to operation,
The whirlpool chamber 14 is filled with pressurized water and compressed air is blown into the high pressure stage runner chamber 8 to push the water below the high pressure stage runner chamber 8 down through the return passage 10 and the low pressure stage runner chamber 9 to the lower part of the suction pipe 16. The runner shall be idle in the power generation direction or pumping direction (first
(see figure). In order to shift from such an idling operation state to power generation operation or pumping operation, first open only the exhaust valve 20 on the exhaust pipe 18 connected to the low pressure stage runner chamber 9 to release the compressed air in the low pressure stage runner chamber 9. is discharged to the outside.

Then, the water in the suction pipe 16 gradually rises and fills the low pressure stage runner chamber 9, and this filled water is pressurized by the rotation of the runner 3 in the low pressure stage runner chamber, and this pressurized water is The water flows toward the return passage 10 while compressing the air within the return passage 10. As shown in FIG. 2, when the water passes between the stay vanes 12 and reaches the middle of the return passage 10, the water is pressurized by the centrifugal action of the low-pressure stage runner 3. When the boundary between the air phase on the high-pressure stage side and the water-filled phase from the low-pressure stage reaches the water level near the center of the turning part of the return passage 10, the exhaust pipe 17 on the high-pressure stage runner chamber 8 side Open the upper exhaust valve 19 and remove the high pressure stage runner chamber 8.
Start discharging the compressed air inside. Note that the state of the water pressure and water level in the low pressure stage runner chamber 9 can be detected by a pressure detector or a water level detector provided on the outer periphery of the low pressure stage runner chamber 9. The detection signal may be transmitted to the exhaust valve 19 on the high pressure stage side to open the valve. At the same time as the high-pressure stage side is exhausted, the water pressurized by the low-pressure stage runner 3 gradually enters the high-pressure stage runner chamber 8 via the return passage 10 and fills the high-pressure stage runner chamber 8 from below. .

When the high pressure stage runner chamber 8 is completely filled with water and reaches the underwater cut-off state, and reaches the specified cut-off pressure or water level, the exhaust valves 19 and 20 are closed to end the exhaust, and the guide vane 15 is moved to a predetermined position. If the opening is increased, it is possible to shift to the required power generation operation or pumping operation. To detect the water-filled state in the low-pressure stage runner chamber 9, a pressure detector or a water level detector may be used as described above, or alternatively, the water-filled state in the low-pressure stage runner chamber 9 may be detected until a predetermined water-filled state is reached. The exhaust valve 19 may be opened after a predetermined period of time has elapsed from the opening of the exhaust valve 20 using a timer device by predicting the time required for filling the exhaust valve 20 with water.

Although the above-mentioned embodiment describes an example in which the present invention is applied to a two-stage pump water turbine, the present invention can of course be applied to a multi-stage hydraulic machine having three or more stages.

As is clear from the above description, according to the present invention, the runner chamber of the low pressure stage is evacuated before the runner chamber of the adjacent high pressure stage, and the water-filled phase from the low pressure stage side and the air phase from the high pressure stage side are separated. Since the runner chamber of the adjacent high pressure stage starts to be exhausted when the boundary of It is possible to avoid exhaust congestion phenomena that would cause air to stagnate, and it is possible to smoothly fill the runner chambers of all stages with water, as well as to bring the runner chamber of the highest pressure stage into a closed state and prevent air from each stage. At the same time as the exhaust is finished, the card f vane is opened, allowing a smooth transition to power generation operation or pumping operation.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing a Francis-type two-stage pump-turbine to which the present invention is applied in an idling state, and FIG. 2 is a vertical cross-sectional view showing the pump-turbine in a state in the middle of exhaust and water filling operation. .

Claims (1)

[Claims] 1. Operation of a multistage hydraulic machine in which the runner chambers of each stage from the lowest pressure stage to the highest pressure stage are connected by a return passage, and only the highest pressure stage is provided with a movable guide vane. In the control method: the movable guide vane is fully closed, the water in the runner chamber is pushed down to the bottom of the runner chamber at the lowest pressure stage by air supply, and the runners in each stage are idled in the direction of the water turbine or pump, and power generation is started. When shifting to operation or pumping operation, first, while exhausting only the compressed air in the runner chamber of the lowest pressure stage, the water in the suction pipe is charged into the lowest pressure stage runner chamber, and the water filling phase and high pressure from the same runner chamber are discharged. When the boundary with the air phase on the stage side reaches near the center of the folded part of the return passage, the compressed air in the adjacent high-pressure stage runner chamber begins to be exhausted, thereby causing the pressurized water in the low-pressure stage runner chamber to flow through the return passage. water is introduced into the runner chamber of the next stage through the runner chamber, and the water is sequentially evacuated and filled at each stage from the lowest pressure stage to the highest pressure stage, until the highest pressure stage runner chamber reaches the specified pressure or water level at which the water is closed under water. Operation of a multi-stage hydraulic machine characterized by stopping the exhaust from the runner chambers of each stage when reaching the maximum, and then opening the movable guide vanes to a predetermined opening degree to shift to power generation operation or pumping operation. Control method. 2. It is detected that the boundary between the water-filled phase from the runner chamber on the low-pressure stage side and the air phase on the high-pressure stage side has reached near the center of the turning part of the return passage, and this detection signal is used to 2. The operation control method according to claim 1, wherein an exhaust valve of an exhaust pipe is opened.