JPS6225876B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of operating a multi-stage hydraulic machine, and in particular, the present invention relates to a method for operating a multi-stage hydraulic machine, in particular, in which each stage from the highest pressure stage to the lowest pressure stage is connected by a return passage, and the highest pressure stage is connected to the lowest pressure stage by a return passage. In multistage hydraulic machines with only movable guide vanes,
The present invention relates to a method of operating a multistage hydraulic machine when switching from power generation operation or pumping operation to idling operation in the direction of generation or pumping, respectively.

In general, in hydraulic machinery, water turbine power generation operation or
When switching from pump pumping operation to turbine control phase operation or pump pumping standby operation, in order to reduce the runner drive torque, the flow path is is driving the runner in the air by pushing down the water. 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, when switching from power generation operation or pumping operation to respective idling operation, Various problems tend to occur with air supply and drainage. In particular, in multi-stage hydraulic machines in which a movable guide vane is installed only in the highest pressure stage to safely control operating conditions during transient times, the flow paths of each stage from the highest pressure stage to the lowest pressure stage are constantly connected. Therefore, when high-pressure air is supplied to the flow passage section, mutual interference between the various stages is likely to occur, and it is difficult to smoothly discharge the supplied air, which poses a problem in the air supply method.

However, there are many technologically unexplored fields in the multistage hydraulic machine itself, which has movable guide vanes only in the highest pressure stage, and it is difficult to smoothly switch from power generation operation or pumping operation to the required idling operation. The reality is that an accurate driving method has not yet been established.

Therefore, an object of the present invention is to make it possible to safely and reliably drain air supply and drain when switching from power generation operation or pumping operation to idling operation, and to enable a smooth transition to idling operation in a short time. An object of the present invention is to provide a method for idling a multi-stage hydraulic machine.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the first invention of the method for operating a multistage hydraulic machine of the present invention will be described with reference to the drawings. Figure 1 shows a Francis type two-stage pump turbine as an example of a multi-stage hydraulic machine. A high-pressure stage runner 2 and a low-pressure stage runner 3 are fixed on the shaft of a single pump-turbine main shaft 1 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. are doing. Furthermore, 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 disposed outside the high-pressure stage runner chamber 8 , and the inlet of the spiral chamber 14 is connected to a penstock 17 via an inlet valve 16 . 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). An elbow-shaped suction pipe 18 is connected to the low-pressure stage runner chamber 9, and the downstream side thereof communicates with a discharge channel 20 via a suction pipe outlet valve 19. A drain pipe 21 is connected to the outer periphery of the high-pressure stage runner chamber 8, while a drain pipe 22 is connected to the outer periphery of the low-pressure stage runner chamber 9, and drain valves 23 and 24 are installed on each pipe. Each drain pipe communicates with a suction pipe 18.

Further, an air supply pipe 25 is provided at the upper part of the suction pipe section 18.
is connected, and an air supply valve 26 is installed on the pipe. Further, a water level detector 27 for detecting the water level in the suction pipe is installed above the suction pipe 18, and a pressure detector 28 for detecting the pressure in the runner chamber is installed in the high pressure stage runner chamber.

When operating the two-stage pump turbine configured as described above, the pressure sent from the penstock 17 through the opened inlet valve 16 flows into the spiral chamber 14 of the spiral casing 13, and this water flow The water passes through the movable guide vane 15 of the high-pressure stage section, flows through the high-pressure stage runner 2, the return passage 10, the low-pressure stage runner 3, passes through the suction pipe 18, and flows into the discharge channel 20.

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 flows from the water discharge channel 20 through the reverse route to the water turbine operation described above. Iron pipe 1
It will be distributed to 7.

Next, we will describe an operating method when applying the embodiment of the first invention of the present application to the above-mentioned two-stage pump turbine and transitioning from the turbine power generation operation or pump pumping operation to idle operation in the direction of the turbine or pump. . To shift from water turbine power generation operation or pump pumping operation to idling in the power generation direction or pumping direction, first move the highest pressure stage movable guide vane 1.
5, and the inlet valve 16 are fully closed simultaneously or sequentially, and when the highest pressure stage movable guide vane 15 is fully closed or close to a small opening, the upper part of the suction pipe 18 communicating with the lower part of the low pressure stage is Open the air supply valve 26 of the connected air supply pipe 25, start supplying air above the suction pipe, and push the water level down to the prescribed position of the suction pipe (see Figure 1).

Next, the drain valve 24 is opened to drain the water remaining in the outer periphery of the low-pressure stage runner chamber 9 and the return passage 10 to the suction pipe 18 via the low-pressure stage drain pipe 22 (see FIG. 2).

It should be noted that whether the water level in the suction pipe section has reached the specified position is determined by a pressure detector (not shown) provided in the low-pressure stage runner chamber 9 to which the suction pipe 18 is connected or a water level detector 27 provided in the suction pipe 18. The drain valve 24 may be opened based on this detection signal. After that, when the pressure inside the high-pressure stage runner chamber 8 becomes lower than the specified value, the drain valve 23 is opened and the water remaining in the outer periphery of the high-pressure stage runner chamber 8 is sucked out through the high-pressure stage drain pipe 21. It is discharged into pipe 18. Furthermore, after the water surface in the suction pipe 18 is stabilized at the specified position described above, the air supply valve 2 of the air supply pipe 25
6 is closed to terminate the supply of air into the suction pipe 18, and each runner is put into idling operation (see FIG. 3).

Incidentally, it is sufficient to detect that the pressure in the high-pressure stage runner chamber 8 has reached a specified state by a pressure detector 28 provided in the runner chamber, and a detection signal from this pressure detector is transmitted to the drain valve 23. All you have to do is open your mouth. Further, whether the water in the suction pipe 18 has stabilized at a specified water level is detected via a water level detector 27 provided at the upper part of the suction pipe, and the air supply valve 26 is closed based on this detection signal.

As is clear from the above description, according to the embodiment of the first invention of the present application, when first pushing down the water surface of the inner flow path of the high-pressure stage movable guide vane, the high-pressure stage guide vane is fully closed. Since air is supplied only to the suction pipe section that has the lowest pressure in the flow path of a two-stage pump-turbine, an economical air supply device such as a compressor with a small pressure capacity can be used, and air supply control can be achieved. It can be simplified, and in addition, since the supply air pressure is not applied directly to the runner, it is safe because it does not induce axial thrust that pushes the rotating part in the axial direction.

By supplying the compressed air, the water in the runner chamber of the low-pressure side stage is first pushed down, and the outer periphery of the runner chamber, excluding the high-pressure stage, is communicated with the suction pipe section via the drain pipe. Water accumulated on the outer periphery of the runner chamber can be accurately drained from the runner chamber drain pipe in a short time by using the centrifugal force of the runner.

In this way, the drainage area by compressed air is expanded sequentially from the low-pressure stage to the high-pressure stage, thereby avoiding instability due to mutual interference of water in each stage during drainage, and ensuring smooth drainage. Ru.

After supplying and draining air in this way, for the high-pressure stage runner chamber that is under the highest pressure among each flow path, the pressure in the high-pressure stage runner chamber is reduced to a safe specified pressure, and then the outer periphery of the runner chamber is Since the water stagnant in the runner chamber is discharged from the runner chamber drain pipe to the suction pipe section, water can be drained smoothly and accurately by the centrifugal force of the runner that is regulated to a safe pressure.

Next, the second method of operating a multi-stage hydraulic machine of the present invention will be described.
Examples of the invention will be described with reference to the drawings. In FIG. 1, which is the same as the embodiment of the first invention of the present application, a vent pipe 29 communicating with the atmosphere is installed above the swirl chamber 14 of the spiral casing 13, and a vent valve 30 is installed on the pipe. is included. Furthermore, the casing swirl chamber 14 and the suction pipe 18
A casing drain pipe 31 is installed with a drain valve 32 installed on the pipe. Further, the suction pipe 18 is provided with an external drain pipe 33 that communicates with a drainage pit (not shown) disposed outside and below the suction pipe 18 and communicating with the atmosphere, and a drain valve 34 is installed on the pipe. , the other configurations are the same as the embodiment of the first invention of the present application.

The water turbine of the two-stage pump turbine configured in this way,
The movement of the water flow during pump operation is the same as in the above-described embodiment of the first invention of the present application.

Next, a method will be described in which the embodiment of the second invention of the present application is applied to this two-stage pump water turbine to shift from water turbine power generation operation or pump pumping operation to idling operation in the water wheel direction or pump direction.
First high pressure stage movable guide vane 15, inlet valve 1
The method from the closing operation of 6 to the state corresponding to FIG. 3 is the same as the embodiment of the first invention of the present application. That is, for the inner flow path portion of the fully closed movable guide vane 15, the water surface is pushed down by the air supply/drainage control according to the embodiment of the first invention of the present application, and then the outer flow path portion of the movable guide vane 15 is pressed down. The water surface of the spiral casing 13 is pushed down as follows.

That is, in the idle running state shown in FIG. 3, first, the suction pipe outlet valve 19 is fully closed, and then the external drain valve 34 of the suction pipe 18 is opened to drain the water in the suction pipe 18 to the external drain pipe 33. At the same time, the casing drain valve 32 and the casing vent valve 30 are opened to allow the inside of the spiral casing 13 to communicate with the atmosphere through the ventilation pipe 29, while draining the water inside the spiral casing 13 into an external drainage pit. The water is discharged by gravity flowing down into the suction pipe 18 through the casing drain pipe 31, thereby lowering the water level in the spiral casing 13 (see FIG. 4).

The water remaining in one sealed space is first communicated with the lower atmospheric pressure section by opening the external drain valve 34, and then communicated with the lower atmospheric pressure section as the other end of the casing vent valve 30. Due to the opening,
These remaining waters are communicated with the upper atmospheric pressure area,
Due to the height difference between the atmospheric pressure water level at the end of the lower external drain pipe 33 and the position where the remaining water is located, the remaining water is discharged under atmospheric pressure.

The control valves of the casing drain valve 32, the casing ventilation valve 30, and the external drain valve 34 either detect that the suction pipe outlet valve 19 is fully closed via a limit switch (not shown), or detect that the suction pipe outlet valve 19 is fully closed. The control valves may be detected via a timer device (not shown) which is set in advance to operate after the valve 19 is fully closed, and the above-mentioned control valves may be opened simultaneously or sequentially based on this detection signal.

As described above, according to the embodiment of the second invention of the present application, when pushing down the water surface of the spiral casing, which is the outer flow path section of the high-pressure stage movable guide vane, the spiral casing is ventilated with the atmosphere and sucked out. Since the water in the spiral casing is allowed to naturally flow down to the suction pipe section through the casing drain pipe while no waterway pressure is applied to the pipe section, there is a risk of compressed air acting inside the spiral casing. The water surface can be safely pushed down without causing any damage, and this prevents the water in the spiral casing from leaking into the runners through the gaps in the movable guide vanes of the high-pressure stepped section, thereby minimizing idling losses. Economical idling operation can be performed with reduced idling.

Although the above-described embodiments of the first and second inventions of the present application are applied to a two-stage pump turbine, the present invention can of course be applied to a multi-stage hydraulic machine having three or more stages.

As described above, a runner is provided in each stage from the highest pressure stage to the lowest pressure stage, the runner chambers of each stage are connected by a return passage, and a movable guide vane is installed only in the highest pressure stage. According to the present invention, there is provided an operation method that can be performed simply, quickly, accurately, and smoothly when shifting from power generation operation or pumping operation to idling operation in the power generation direction or pumping direction, respectively, in a multistage hydraulic machine equipped with the above. This can be said to be extremely reasonable.

[Brief explanation of the drawing]

1 and 2 are longitudinal cross-sectional views showing states in the middle of air supply and drainage operation of a Francis type two-stage pump turbine to which an embodiment of the present invention is applied, and FIGS. 3 and 4 are the same. FIG. 3 is a cross-sectional view showing the idling operation state of the pump-turbine. 2... High pressure stage runner, 3... Low pressure stage runner, 8... High pressure stage runner chamber, 9... Low pressure stage runner chamber, 10... Return passage, 13... Spiral casing, 15... Movable guide vane, 16... Inlet valve, 18... Suction pipe, 19
... Suction pipe outlet valve, 21, 22, 31... Drain pipe,
23, 24, 32, 34...drain valve, 25...air supply pipe, 26...air supply valve, 29...ventilation pipe, 30...ventilation valve.

Claims (1)

[Claims] 1. A runner is provided in each stage from the highest pressure stage to the lowest pressure stage, the runner chambers of each stage are connected by a return passage, and a movable guide vane is provided only in the highest pressure stage. In the operating method of a multi-stage hydraulic machine equipped with a multi-stage hydraulic machine, when transitioning from water turbine power generation operation or pump pumping operation to power generation phase adjustment or pumping standby idle operation, the highest pressure stage is connected to the lowest pressure stage in a state where the highest pressure stage is connected to the lowest pressure stage. When the highest pressure stage guide vane is fully closed or close to a small opening, air is supplied to the upper part of the suction pipe connected to the lower part of the lowest pressure stage, and the suction pipe is closed. When the water level has been lowered to the specified position in the lower pressure stage, the water in the outer periphery of the low pressure stage runner chamber, excluding the highest pressure stage part, is sequentially discharged from the low pressure stage side through the outer peripheral drain pipe of the low pressure stage runner chamber to the suction pipe part, When the pressure in the highest pressure stage runner chamber reaches the specified value or less, the water in the outer periphery of the highest pressure stage runner chamber is discharged to the suction pipe section through the highest pressure stage runner chamber outer peripheral drain pipe, and the water level in the suction pipe section is lowered. The multi-stage hydraulic machine is characterized in that, when it is stabilized at the specified position, the air supply to the suction pipe section is stopped and the water in the flow path is pushed down from the highest pressure stage section to the lowest pressure stage section, thereby performing idling operation. how to drive. 2 A multistage hydraulic machine in which a runner is provided in each stage from the highest pressure stage to the lowest pressure stage, the runner chambers of each stage are connected by a return passage, and a movable guide vane is provided only in the highest pressure stage. In the operation method, when transitioning from water turbine power generation operation or pump pumping operation to generation phase adjustment or pumping standby idle operation, the highest pressure stage guide vane and inlet valve are connected to each other from the highest pressure stage to the lowest pressure stage. When the highest pressure stage guide vane is fully closed or close to a small opening, air is supplied above the suction pipe connected to the lower part of the lowest pressure stage, and the water level reaches the specified position of the suction pipe. When the water is pushed down, the water in the outer periphery of the low-pressure stage runner chamber, excluding the highest pressure stage part, is sequentially discharged from the low-pressure stage side to the suction pipe section through the drain pipe of the outer peripheral part of the low-pressure stage runner chamber. Once the pressure has reached the specified value or below, the water on the outer periphery of the highest pressure stage runner chamber is discharged to the suction pipe section via the highest pressure stage runner chamber outer peripheral drain pipe, and the water level in the suction pipe section is stabilized at the specified position. The supply of air to the above-mentioned suction pipe section is terminated, and the suction pipe outlet valve provided in the suction pipe section or the draft tunnel section downstream thereof is fully closed. The drain valve of the external drain pipe that connects to the drain pit is opened to drain the water in the suction pipe to the drain pit, and the vent valve of the vent pipe that opens at the top of the casing is opened to communicate with the atmosphere. The idling operation is performed by draining the water in the casing section between the fully closed inlet valve and the highest pressure stage guide vane through the casing drain pipe to the suction pipe section by gravity. How to operate a multi-stage hydraulic machine.