JPH04279772A - Hydraulic machinery and method for activating and controlling it - Google Patents

Abstract

PURPOSE:To reduce stress acting on runners when hydraulic machinery is started for power generation or when pumping operation is transferred to generating operation. CONSTITUTION:At start-up for power generation, a movable guide vane is opened to an activating opening. Then, an inlet valve is opened to a relatively small given opening to introduce pressurized water to runners. The rotational speed of the runners is detected and when the speed reaches a given value, the inlet vale is fully opened. When introduction of pressurized water is started to the runners, the water flows along the runners because the guide vane has already been opened to the activating opening and the inlet valve has a relatively small opening.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to hydraulic machines such as water turbines and pump turbines, and methods for starting and controlling them, and particularly to hydraulic machines equipped with an inlet pipe, an inlet valve, a casing, a movable guide vane, and a runner. The present invention relates to its activation and control method.

0002

[Prior Art] A hydraulic machine with movable guide vanes is
Generally, the turbine is started by opening the guide vanes and introducing pressure water into the runner.

FIG. 10 shows a general pump turbine having movable guide vanes. During power generation operation, pressurized water from the inlet pipe 1 flows into the casing 3 through the inlet valve 2, and the movable guide vanes flow into the casing 3. It flows into the runner 5 via the blade 4, is driven to rotate, and is discharged from the suction pipe 6.

[0004] When starting the power generation of this hydraulic machine, FIG.
As shown in a), the opening degree ai of the inlet valve 2 is set at time T1.
The casing 3 is opened from the fully closed state to the fully open position, and the casing 3 is filled with pressurized water. When the inlet valve 2 is fully opened at time T2, the guide vane 4 opens as shown in FIG. 11(b).
Open the opening ag from the fully closed state to the predetermined starting opening,
Pressure water is introduced into the runner 5 and the rotation of the runner 5 is started. When the opening ag of the guide vane 4 reaches the predetermined starting opening at time T3, the guide vane 4 is further gradually opened and the rotation speed of the runner reaches the target rotation as shown in FIG. 11(c). Set rotational speed below the number number, e.g. target rotational speed N
At time T4 when approximately 80% of o is reached, control of the runner rotational speed by a governor (not shown) is started, and the guide vane opening degree ag is adjusted so as to reach the target rotational speed No.

FIG. 12 shows the relationship between the absolute flow velocity V of the pressure water flowing into the runner 5 from the guide vane 4, the circumferential velocity U of the runner vane 7, and the relative velocity W of the pressure water in a steady operating state. . In this steady operating state, since the opening degree ag of the guide vane 4 is large, the flow angle α of the absolute flow velocity V is relatively large, and the guide vane 7 is rotating at a large circumferential velocity U, so that the relative velocity W and the runner vane The difference β from the entrance angle of 7 becomes small. Therefore, the pressure water flows smoothly along the runner blade 7, and the stress σ acting on the runner blade 7 is extremely small as shown in FIG. 11(d).

[0006] The above operation is the same for general water turbines other than pump water turbines. In addition, when the pump-turbine shifts from pumping operation to power generation operation, when it receives a power generation operation switching command at time T1 during pumping operation as shown in FIG. 13(a), While the opening degree ai of the inlet valve 2 remains 100%, the opening degree ag of the guide vane 4 is closed to a predetermined small opening degree as shown in FIG. 13(b). During this time, as shown in FIG. 13(d), the generator motor is disconnected from the power grid at time T2, and the pump direction input P to the generator motor is made zero. As a result, the runner 5 gradually shifts from rotation in the direction of the pump to rotation in the direction of the water wheel due to the potential energy of the water in the upper pond. Guide vane 4 is at time T3
When the opening reaches a predetermined small opening, it is maintained at this small opening.

As shown in FIG. 13(c), when the rotational speed N of the runner 5 in the pump direction reaches around zero at time T4,
The guide vane opening ag is opened to the power generation starting opening. When it is detected at time T5 that the runner rotational speed N has reached, for example, 80% of the target rotational speed No., the governor (not shown)
rotation control is started, and the guide vane opening degree ag is adjusted so that the target rotational speed No. is reached.

FIG. 14 shows the pumping operation, that is, the time T in FIG.
13(e), the direction of the relative velocity W is along the runner blade 7, and the stress σ acting on the runner 5 is small as shown in FIG. 13(e).

[0009]

[Problems to be Solved by the Invention] However, in conventional hydraulic machines, since the guide vane opening degree ag is small at the time of starting power generation, the flow angle α is small as shown in FIG. 15, and the absolute speed V
is big. Further, since the runner 5 is stationary or rotates at a low speed, the circumferential speed U of the runner blade 7 is very small. Therefore, the difference β between the direction of the relative velocity W of water and the entrance angle of the runner blade 7 becomes large, and the water at the relative velocity W collides with the runner blade 7 almost perpendicularly, causing a large impact force to act on the blade surface. Therefore, as shown in FIG. 11(d), a large stress σ acts on the root portion of the runner blade 7 at the time of starting power generation.

[0010] Also, when the pump-turbine is switched from pumping operation to power generation operation, a large stress σ is generated at the base of the runner blade near time T4, as shown in Fig. 13(e).
acts. This is because the opening of the guide vanes is small and the circumferential speed of the runner vanes is almost zero, as at the time of power generation start-up mentioned above, so the relative velocity W becomes equal to the absolute velocity V as shown in Fig. 16, and the relative velocity of the water This is because the difference β between the direction of the velocity W and the entrance angle of the runner blade 7 is large, and the water at the relative velocity W collides with the runner blade 7 almost perpendicularly.

[0011] Such a large stress is generated every time power generation is started.
Alternatively, if it acts on the runner 5 every time the pumping operation is switched to the power generation operation, there is a problem that fatigue failure of the runner 5 may occur. Particularly in high-head hydraulic machines, the repeated stress that acts on the base of the runner blade during operation is extremely large, and in addition to this, the water flow from the guide blade 4 at startup is high-speed, so the runner blade 7 is subjected to The impact force is also large, significantly reducing the fatigue strength of the runner, and increasing the risk of fatigue failure and breakage.

[0012] Accordingly, it is an object of the first invention of the present application to provide a method for starting a hydraulic machine that can sufficiently reduce the stress acting on the runner blades when the hydraulic machine starts generating electricity. A second object of the present invention is to provide a method for controlling a hydraulic machine that can sufficiently reduce the stress acting on the runner blades when the hydraulic machine shifts from pumping operation to power generation operation. A third object of the present invention is to provide a hydraulic machine that can sufficiently reduce the stress acting on the runner blades at the time of starting power generation.

[0013]

[Means for Solving the Problem] To achieve this object, a method for starting a hydraulic machine according to the first invention of the present application is a method for starting a hydraulic machine equipped with an inlet valve, a movable guide vane, and a runner. , a step of opening the guide vane to a predetermined starting opening, a step of opening the inlet valve from a fully closed state to a relatively small predetermined opening after opening to the predetermined starting opening, and a step of opening the guide vane to a relatively small predetermined opening of the runner. The present invention is characterized by comprising a step of detecting a rotational speed and opening the inlet valve to a full opening degree when the detected rotational speed reaches a predetermined value.

[0014] A method for controlling a hydraulic machine according to a second invention of the present application includes an inlet valve, a movable guide vane, and a runner,
In a method for controlling a hydraulic machine capable of switching between pumping operation and power generation operation, a first step of closing the guide vane to a predetermined opening degree during pumping operation, and a step of opening the inlet valve from a fully open state during this first step. The second door closes to a predetermined small opening.
a third step of disconnecting the generator motor of the pump-turbine from the power system during the second step, and detecting the rotational speed of the runner, and determining that the detected rotational speed value is a predetermined value in the rotational direction of the power generation operation. The invention is characterized by comprising the step of opening the inlet valve to a full opening degree when the opening degree is reached.

A hydraulic machine according to a third aspect of the present invention is a hydraulic machine including an inlet pipe, a casing, a movable guide vane, and a runner, wherein at least one of the inlet pipe and the casing, the guide vane, and the runner are provided. A bypass pipe that communicates with the flow path between the runners, a control valve installed in the bypass pipe, and a control device that opens the control valve before the guide vane opens when the hydraulic machine is started. It is characterized by:

[0016]

[Operation] The operation of the first invention will be described below. First, the guide vanes are opened to a predetermined startup opening degree, and then the inlet valve is opened from a fully closed state to a relatively small predetermined opening degree, and pressurized water is introduced into the runner to rotate the runner. When pressure water is introduced into the runner, the guide vanes have already opened to the starting opening, so the flow angle α of the absolute velocity of the pressure water becomes large.
Furthermore, since the inlet valve opening is small, the absolute speed is small. Therefore, even though the circumferential speed of the runner blades is small, the angle between the direction of the relative velocity of the pressure water and the direction of the runner blades is significantly smaller than before, and the stress acting on the runner blades is also significantly reduced. do.

The operation of the second invention is as follows. The guide vanes are closed to a predetermined opening during pumping operation. This first
During the process, the inlet valve is closed from a fully open state to a predetermined small opening. In the middle of this second step, the generator motor of the pump-turbine is disconnected from the power system, water pumping is stopped, and power generation start operation is started. At the start of power generation, the guide vanes are set in advance to a predetermined opening, so the flow angle of the absolute velocity of the pressure water is large, and the inlet valve is set to a predetermined small opening, so the absolute velocity is small. Therefore, even though the circumferential speed of the runner blades is small, the angle between the direction of the relative velocity of the pressure water and the direction of the runner blades is significantly smaller than before, and the stress acting on the runner blades is also significantly reduced. do.

The operation of the third invention is as follows. When starting the water turbine, the control device opens the control valve before opening the guide vanes. This allows pressurized water from the inlet pipe or the casing to bypass the guide vanes and flow into the runner via the bypass pipe, pre-rotating the runner. After the runner peripheral speed becomes sufficiently large due to this pre-rotation of the runner, the guide vanes are opened. Therefore, the pressure water flowing into the runner from the guide vanes flows along the runner blades and does not exert a large force on the runner blades.

[0019]

[Example] An example of a hydraulic machine according to the present invention is shown below in Figure 1.
1, in which the same parts as in FIGS. 0 to 16 are given the same reference numerals.
This will be explained with reference to FIGS. The method for starting a hydraulic machine according to the first invention of the present application and the method for controlling a hydraulic machine according to the second invention can also be applied to the conventional hydraulic machine shown in FIG. An example applied to a hydraulic machine will be described.

In FIGS. 1, 2, and 10, when a power generation start command is issued at time T1, the opening degree ag of the movable guide vane 4 becomes relatively large as shown in FIG. 2(b). When the predetermined starting opening degree is reached at time T2, this opening degree is maintained. Opening degree ai of inlet valve 2
As shown in FIG. 2(a), the opening is opened from the fully closed state to a relatively small predetermined opening at time T2, and is maintained at this predetermined opening. When the inlet valve 2 starts opening, pressurized water is introduced from the inlet pipe 1 into the runner 5 via the inlet valve 2, casing 3, and guide vane 4, and drives the runner 5 to rotate.

A rotation detector (not shown) is connected to this runner 5.
The detected rotation speed is shown in Figure 2(c).
As shown in FIG. 3, at time T3 when the predetermined rotational speed N is reached, the inlet valve 2 is opened to the full opening degree. Thereafter, when the runner rotational speed N reaches a predetermined set value, for example, about 80% of the target runner rotational speed No., at T4, control of the runner rotational speed by a governor (not shown) is started, and the target runner rotational speed No. Adjust the guide vane opening ag so that

In this way, when the pressure water starts flowing into the runner 5, as shown in FIG. Since the flow angle α becomes large and the opening degree of the inlet valve 2 is small, the absolute velocity V has a small value. Therefore, even though the circumferential speed U of the runner blade 7 is small, the angle β between the direction of the relative velocity W of the pressure water and the direction of the runner blade 7 is significantly smaller than that in the conventional case, as shown in FIG. 2(d). As shown in FIG. 2, the stress α acting on the runner blades 7 at the time of starting power generation is also significantly reduced.

Note that it is desirable that the starting opening of the guide vane 4 is set to the no-load opening. By setting this no-load opening, it is possible to prevent the runner rotation speed from exceeding the target rotation speed No. even if the governor is unable to control the runner rotation speed normally due to a failure etc. .

FIG. 4 shows a time diagram of a modification of the embodiment of the first invention, in which the starting opening degree of the guide vane 4 is made larger than that in FIG. 2. As a result, the rotational speed N of the runner 5 increases more rapidly than in the case of FIG. 2, and reaches 80% of the target rotational speed No at time T4 before the inlet valve 2 is fully opened.
Governor control is started from this point T4.

In this modification, since the starting opening of the guide vane 4 is large, the flow angle α shown in FIG. can. Additionally, the time required for power generation start-up operation is also shortened.

Next, an embodiment of a method for controlling a hydraulic machine according to the second invention of the present application will be described. During pumping operation, when a power generation operation switching command is generated at time T4 as shown in FIG. 5, the guide vanes 4 are closed to a relatively large predetermined opening as shown in FIG. 5(b). Guide vane opening a
When g reaches a predetermined opening degree at time T4, this opening degree is maintained. The opening degree ai of the inlet valve 2 starts from the fully open state at time T2 as shown in FIG. 5(a), and closes at time T5.
When a small predetermined opening degree is reached, the opening degree is maintained at this predetermined opening degree.

When the generator motor (not shown) is disconnected from the power grid at time T3 as shown in FIG. 5(d), the runner rotation speed N in the pump direction increases as shown in FIG. 5(c). starts decelerating, becomes zero at time T6, and starts rotating in the direction of the water wheel. The rotational speed N in the direction of the water wheel is at time T
When it is detected that the first predetermined speed set in advance is reached at step 7, the inlet valve 2 is further opened to the full extent as shown in FIG. 5(a).

[0028] The runner rotational speed N in the water turbine direction is a second predetermined speed, for example, 80% of the target rotational speed No.
At time T8 when the rotational speed reaches the target rotational speed No., the governor starts controlling the runner rotational speed and adjusts the guide vane opening degree ag so that the target rotational speed No. is reached.

FIG. 6 shows a speed triangle when the runner rotational speed N is zero, that is, at time T6 in FIG. 5. Since the circumferential speed of the runner blade 7 is zero, the relative speed W becomes the absolute speed V. Match. Since the guide vanes 4 are set to a relatively large opening, the flow angle of the absolute velocity V of the pressure water is large, and since the inlet valve is set to a predetermined small opening, the absolute velocity V is small. Therefore, even though the circumferential speed of the runner blade 7 is zero, the angle β between the direction of the relative velocity W of the pressure water and the direction of the runner blade 7 is significantly smaller than that in the past, and the effect on the runner blade is The stress caused by this process is also significantly reduced.

[0030] In this embodiment as well, the guide vane opening can be set to the no-load opening during power generation operation, as in the case of the first invention. FIG. 7 shows a time diagram of a modification of the embodiment of the second invention, in which the runner rotational speed N becomes zero at time T6.
The opening degree of the inlet valve 2 is changed after . That is, the opening degree of the inlet valve 2 between time points T5 and T6 is extremely small, and the opening degree between time points T6 and T7 is set to be larger than that. As a result, the runner blade stress α when the runner rotational speed N is near zero, particularly just before the runner rotational speed N becomes zero, can be further reduced as shown in FIG. 7(e).

FIG. 8 shows an embodiment of a hydraulic machine according to the third invention of the present application, in which one end of a bypass pipe 8 is connected to the casing 3, and the other end of the bypass pipe 8 is connected to the guide vane 4. and the runner 5. In this way, the bypass pipe 8 bypasses the guide vane 4 and communicates the casing 3 with the flow path 9. A control valve 10 is installed in the bypass pipe 8, and this control valve 10 is connected to a control device 11.
Opening/closing is controlled by the output of A rotation speed detector (not shown) is installed on the main shaft 12, and this rotation speed detector detects the rotation speed of the runner 5. Other configurations are shown in Figure 1.
The configuration is the same as 0.

[0032] The hydraulic machine is started as follows. After the inlet valve 1 is fully opened, the opening degree ac of the control valve 10 is fully opened at time T1 as shown in FIG. 9(a). As a result, the pressure water that has passed through the inlet pipe 1, inlet valve 2, and casing 3 flows into the flow path 9 through the bypass pipe 8,
From this flow path 9, it passes through the runner 5 and flows out into the suction pipe 6. In this way, the runner 5 is pre-rotated by the pressure water passing through the bypass pipe 8.

Based on the detection output of the rotation speed detector that detects the rotation speed N of the runner 5, the control device 11 determines the time T2 when the runner rotation speed N reaches a predetermined value.
Then, the control valve 10 is fully closed and the guide vane 4 is opened as shown in FIG. 9(b) to increase the runner rotational speed N to the target rotational speed, that is, the rated rotational speed.

[0034] As described above, since the runner 5 is already rotating at a predetermined rotational speed when the guide vane 4 is opened at the time of startup,
The runner circumferential speed U is relatively large, so the relative flow is in the direction along the runner blade 7 compared to the conventional case, as shown in Fig. 9(d).
As shown in , the stress α acting on the runner blade becomes sufficiently small. Further, since the control valve 10 is closed during steady operation, the water flow passing through the bypass pipe 8 does not disturb the water flow from the guide vane 4. In the above embodiment, the bypass pipe 8 communicates the casing 3 and the flow path 9. However, this bypass pipe 8 may also communicate the inlet pipe 1 and the flow path 9.

[0035]

[Effects of the Invention] As is clear from the above description, according to the first invention of the present application, when pressure water is introduced into the runner during power generation, the guide vanes are opened to the starting opening in advance. The absolute velocity of the pressure water is small because the flow angle is large and the inlet valve opening is small. Therefore, the angle between the direction of the relative velocity of the pressurized water and the direction of the runner blades is significantly smaller than before, and the stress acting on the runner blades is significantly reduced, reducing the decrease in fatigue strength of the runner blades. At the same time, it is possible to reduce vibrations around the runner due to the impact of the water flow.

Further, according to the second invention of the present application, since the guide vanes are set to a predetermined opening degree in advance during the transition from pumping operation to power generation start-up operation, the flow angle of the absolute velocity of the pressure water is large. Also, since the inlet valve is set to a predetermined small opening degree, the absolute speed is small. Therefore, the angle between the direction of the relative velocity of the pressurized water and the direction of the runner blades is significantly smaller than before, and the stress acting on the runner blades is also significantly reduced, reducing the decrease in fatigue strength of the runner blades. At the same time, it is possible to reduce vibrations around the runner due to the impact of the water flow.

According to the third invention of the present application, when the water turbine is started, the runner rotates in advance before the guide vanes open and the runner circumferential speed is sufficiently high, so that the pressure water flowing from the guide vanes into the runners is The water flows along the runner blades, and the stress acting on the runner blades is significantly reduced, making it possible to reduce the decrease in fatigue strength of the runner blades and also to reduce the occurrence of vibrations around the runners due to the impact of the water flow.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing an embodiment of a method for starting a hydraulic machine according to a first invention of the present application.

FIG. 2 is a time diagram for explaining the startup method of the above embodiment.

FIG. 3 is a velocity triangle diagram of the runner blade inlet portion during startup of the above embodiment.

FIG. 4 is a time diagram for explaining a modification of the above embodiment.

FIG. 5 is a time diagram for explaining an embodiment of a method for controlling a hydraulic machine according to the second invention of the present application.

FIG. 6 is a velocity triangle diagram of the runner blade inlet portion during startup of the embodiment of the second invention.

FIG. 7 is a time diagram for explaining a modification of the embodiment of the second invention.

FIG. 8 is a sectional view showing an embodiment of a hydraulic machine according to the third invention of the present application.

FIG. 9 is a time diagram for explaining an embodiment of the third invention.

FIG. 10 is a cross-sectional view schematically showing a conventional hydraulic machine.

FIG. 11 is a time diagram for explaining a conventional method for starting power generation in a hydraulic machine.

FIG. 12 is a velocity triangle diagram of the runner blade inlet during steady power generation operation of a conventional hydraulic machine.

FIG. 13 is a time diagram for explaining the operation of a conventional hydraulic machine when it transitions from pumping operation to power generation operation.

FIG. 14 is a velocity triangle diagram of the runner blade inlet during conventional pumping operation.

FIG. 15 is a velocity triangle diagram of the runner blade inlet section when power generation is started in a conventional hydraulic machine.

FIG. 16 is a velocity triangle diagram of the runner blade inlet during transition from conventional pumping operation to power generation operation.

[Explanation of symbols]

1 Inlet pipe 2 Inlet valve 3 Casing 4 Movable guide vanes 5 Runner 6 Suction pipe 7 Runner blade 8 Bypass pipe 9 Flow path 10 Control valve 11 Control device

Claims (3)

[Claims] 1. A method for starting a hydraulic machine comprising an inlet valve, a movable guide vane, and a runner, comprising: opening the guide vane to a predetermined starting opening; and opening the guide vane to the predetermined starting opening. Thereafter, a step of opening the inlet valve from a fully closed state to a relatively small predetermined opening degree, and detecting the rotational speed of the runner and opening the inlet valve to the fully open degree when the detected rotational speed reaches a predetermined value. A method for starting a hydraulic machine, comprising the step of opening the machine. Claim 2: A method for controlling a hydraulic machine that is equipped with an inlet valve, a movable guide vane, and a runner and is capable of switching between pumping operation and power generation operation, the method comprising: opening the guide vane to a predetermined opening degree during pumping operation; A first step of closing the inlet valve, a second step of closing the inlet valve from a fully open state to a predetermined small opening during this first step, and disconnecting the generator motor of the pump water turbine from the power system during this second step. A third step of
Detecting the rotational speed of the runner and opening the inlet valve to a full opening when the detected rotational speed reaches a predetermined value in the rotational direction of power generation operation. Control method. 3. A hydraulic machine comprising an inlet pipe, a casing, a movable guide vane, and a runner, wherein at least one of the inlet pipe and the casing communicates with a flow path between the guide vane and the runner. A hydraulic machine comprising: a bypass pipe; a control valve installed in the bypass pipe; and a control device that opens the control valve before opening the guide vane when the hydraulic machine is started.