JP2945770B2 - Hydraulic machine and its starting and control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic machine such as a water turbine and a pump turbine and a method for starting and controlling the hydraulic machine, and more particularly to a hydraulic machine having an inlet pipe, an inlet valve, a casing, movable guide vanes and a runner. It relates to the activation and control method.

[0002]

2. Description of the Related Art A hydraulic machine having movable guide vanes is
Generally, the guide vanes are opened and pressurized water is introduced into the runner to start the turbine.

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

[0004] At the start of power generation of this hydraulic machine, FIG.
Opened from the fully closed state to the fully opened opening degree at time T ₁ the opening a _i of the inlet valve 2 as shown in (a), is filled with water and pressurized water into the casing 3. When the inlet valve 2 is fully opened at time T _2, the opening a _g of guide vanes 4 as shown in FIG. 11 (b) opens from the fully closed state to a predetermined start opening, introducing pressurized water into the runner 5 Then, the rotation of the runner 5 is started. When opening a _g of guide vanes 4 at T ₃ reaches a predetermined activation opening, is further gradually opened guide blades 4 Thereafter, 11
As shown in (c), the rotation speed of the runner is equal to the target rotation speed N.
_o The set rotation speed below, for example, 80% of the target rotation speed N _o
Once T ₄ reaching extent, to initiate control of the runner rotational speed of the governor (not shown), to adjust the guide vane opening a _g such that the target rotational speed N _o.

FIG. 12 shows the relationship between the absolute velocity V of the pressure water flowing into the runner 5 from the guide blade 4 and the peripheral velocity U of the runner blade 7 and the relative velocity W of the pressure water in a steady operation state. . In this steady operation state, a relatively large flow angle α of the absolute velocity V for opening a _g is large guide vane 4 and since the guide vanes 7 is rotating at a larger peripheral speed U, the relative velocity W and the runner The difference β from the entrance angle of the blade 7 becomes small. Therefore, the pressurized water smoothly flows in along the runner blade 7, and as shown in FIG.
Is very small.

The above operation is the same for general turbines other than pump turbines. Further, when the reversible pump-turbine is transferred to the power generating operation of pumping operation, during the pumping operation, as shown in FIG. 13, when receiving the power generation operation switching command at time T _1, as shown in FIG. 13 (a) the opening a _i of the inlet valve 2 remains 100%, closing the opening a _g of guide vanes 4 as shown in FIG. 13 (b) to a predetermined small degree. During this time, by disconnecting the generator motor from the power grid at the time T ₂ as shown in FIG. 13 (d), to zero the pump direction input P of the generator motor. As a result, the runner 5 gradually shifts from rotation in the pump direction to rotation in the water turbine direction due to the potential energy of the water in the upper pond. Guide vanes 4 is held in the small opening degree when a predetermined small opening at time T _3.

[0007] Pump rotating speed N of the runner 5 as shown in FIG. 13 (c) when at T ₄ reaches the vicinity of zero, opening the guide vanes opening a _g to power activation opening. When detected at T ₅ that runner rotational speed N reaches, for example, 80% of the target rotational speed N _o, the start of the rotation control by the governor (not shown), the guide vanes such that the target rotational speed N _o adjusting the opening a _g.

FIG. 14 shows the time of pumping operation, that is, time T in FIG.
_This shows the velocity triangle of water at ₁ and 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.

[0009]

The object of the invention is to be Solved However, since the conventional hydraulic machine has a small guide vane opening a _g at the time of power generation start-up,
As shown in FIG. 15, the flow angle α is small and the absolute velocity V is large. Further, since the runner 5 is stationary or rotates at a low speed, the peripheral speed U of the runner blade 7 is very small. Therefore,
Difference β between the direction of relative velocity W of water and the inlet angle of runner blade 7
The water at the relative speed W collides with the runner blade 7 almost vertically, and a large impact force acts on the blade surface. For this reason, as shown in FIG. 11D, a large stress σ acts on the root of the runner blade 7 at the time of starting the power generation.

Further, even when switching to a power generating operation from pumping operation of the pump turbine, acts large stress σ to the base portion of the runner blades in the vicinity of the time T ₄ as shown in FIG. 13 (e). This is because the guide vane opening is small and the peripheral speed of the runner vane is almost zero as in the above-described power generation start-up.
As shown in FIG. 16, the relative speed W becomes equal to the absolute speed V, and the difference β between the direction of the relative speed W of the water and the entrance angle of the runner blade 7 is large. This is because they collide vertically.

[0011] Such a large stress is generated every time the power generation is started.
Alternatively, if it acts on the runner 5 every time the operation is switched from the pumping operation to the power generation operation, there is a problem that the fatigue failure of the runner 5 is caused. In particular, in a hydraulic machine with a high head, the repetitive stress acting on the root portion of the runner blade during operation is very large, and in addition to this, the water flow from the guide blade 4 at the time of startup is high, so that the runner blade 7 receives The impact force is large and the fatigue strength of the runner is greatly reduced, and the possibility of fatigue failure and breakage increases.

Accordingly, an object of the first invention of the present application is to provide a starting method of a hydraulic machine capable of sufficiently reducing the stress acting on the runner blades at the start of power generation of the hydraulic machine. It is an object of a second invention of the present application to provide a control method of a hydraulic machine capable of sufficiently reducing the stress acting on the runner blades when the hydraulic machine shifts from the pumping operation to the power generation operation. It is an object of the third invention of the present application to provide a hydraulic machine capable of sufficiently reducing a stress acting on a runner blade at the time of starting power generation.

[0013]

In order to achieve this object, a method for starting a hydraulic machine according to a first invention of the present application is a method for starting a hydraulic machine having an inlet valve, movable guide vanes and a runner. in the above guide vanes and a step of opening up to a predetermined start opening, a step of opening after opening up the predetermined start opening to a relatively small predetermined opening the inlet valve from the fully closed state, the inlet valve While maintaining the specified opening of
Detecting the rotational speed of the runner; and rotating the runner.
Opening the inlet valve to a full opening when the detected speed value reaches a predetermined value.

A control method for 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 control method of a hydraulic machine capable of switching between a pumping operation and a power generation operation, a first step of closing the guide blade to a predetermined opening during the pumping operation, and the inlet valve being fully opened during the first step. Second closing 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 rotation speed of the runner and detecting the rotation speed as a predetermined value in the rotation direction of the power generation operation. And opening the inlet valve to the full opening when the pressure reaches the maximum value.

A hydraulic machine according to a third invention of the present application is 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, the guide vane and A bypass pipe that communicates with a flow path between runners, a control valve installed in the bypass pipe, and a control device that opens the control valve before opening the guide blade when the hydraulic machine is started. It is characterized by the following.

[0016]

The operation of the first invention will be described below. After the guide vanes are first opened to a predetermined starting opening, the inlet valve is opened from a fully closed state to a relatively small opening, and pressurized water is introduced into the runner to rotate the runner. At the time of introducing the pressurized water into the runner, since the guide vanes are already opened at the start opening, the flow angle α of the absolute velocity of the pressurized water increases,
In addition, since the opening degree of the inlet valve is small, the absolute speed is small. Therefore, despite the low peripheral speed of the runner blade, the angle between the direction of the relative speed of the pressurized water and the direction of the runner blade is significantly smaller than in the past, and the stress acting on the runner blade is also significantly reduced. I do.

The operation of the second invention is as follows. During pumping operation, the guide vanes are closed to a predetermined opening. This first
In the middle of the process, the inlet valve is closed from a fully open state to a predetermined small opening degree. In the middle of the second step, the generator motor of the pump turbine is disconnected from the power system to stop pumping, and shifts to the power generation start operation. At the start of the power generation, the guide blades are set to a predetermined opening beforehand, so that the flow angle of the absolute speed of the pressurized water is large, and the absolute speed is small because the inlet valve is set to a predetermined small opening. Therefore, despite the low peripheral speed of the runner blade, the angle between the direction of the relative speed of the pressurized water and the direction of the runner blade is significantly smaller than in the past, and the stress acting on the runner blade is also significantly reduced. I do.

The operation of the third invention is as follows. When the turbine is started, the control device opens the control valve before opening the guide blade. Thereby, the pressurized water from the inlet pipe or the casing flows into the runner via the bypass pipe, bypassing the guide vane, and rotates the runner in advance. After the runner circumferential speed has become sufficiently high due to the pre-rotation of the runner, the guide vanes are opened. Therefore, the pressure water flowing into the runner from the guide blade flows along the runner blade and does not exert a large force on the runner blade.

[0019]

FIG. 1 shows an embodiment of a hydraulic machine according to the present invention.
1 in which the same reference numerals are assigned to the same parts as in FIGS.
This will be described with reference to FIGS. The starting method of the hydraulic machine according to the first invention of the present application and the control method of the hydraulic machine according to the second invention can be applied to the conventional hydraulic machine shown in FIG. An embodiment applied to a hydraulic machine will be described.

[0020] In FIG. 1, 2 and 10, when the power generation start command is generated at time T _1, the opening a _g guide vane 4 movable as shown in FIG. 2 (b) relatively is opened to a large predetermined activation opening, it holds it and at T ₂ reaches the predetermined start opening. The opening _ai of the inlet valve 2 is shown in FIG.
At time T _2, as shown in (a) is opened to a relatively small predetermined opening from the fully closed state, it is held in the predetermined opening degree. When the opening of the inlet valve 2 starts, the pressurized water is introduced from the inlet pipe 1 to the runner 5 through the inlet valve 2, the casing 3, and the guide blade 4, and drives the runner 5 to rotate.

A rotation detector (not shown) is provided with the runner 5.
2c is detected, and the detected value of the rotation speed is shown in FIG.
Inlet valve 2 is opened to the fully open opening when T ₃ reaches a predetermined rotational speed N as shown in. Thereafter, the runner rotation speed N is set to a predetermined value, for example, the target runner rotation speed N.
the T ₄ when it reaches about 80% of the _o, to initiate control of the runner rotational speed of the governor, not shown, to adjust the guide vane opening a _g such that the target runner rotational speed N _o.

As described above, when the flow of the pressurized water into the runner 5 starts, as shown in FIG. 3, the guide blade 4 is already opened at a relatively large starting opening, so that the absolute velocity V of the pressurized water is reduced. Since the flow angle α is large and the opening degree of the inlet valve 2 is small, the value of the absolute speed V is small. Therefore, although the peripheral speed U of the runner blade 7 is low, the angle β between the direction of the relative speed W of the pressure water and the direction of the runner blade 7 is significantly smaller than in the conventional case, and FIG. As shown in (1), the stress α acting on the runner blades 7 at the start of power generation is also greatly reduced.

It is desirable that the opening of the guide vanes 4 be set to a no-load opening. By setting to the no-load opening, even if the governor is no longer able to perform the control of the normal runner rotational speed due to a failure or the like, prevents the runner rotational speed may exceed a target rotational speed N _o it can.

FIG. 4 is a time chart of a modification of the first embodiment of the present invention, in which the starting opening of the guide vanes 4 is made larger than that in FIG. This rotational speed N of the runner 5 is increased more rapidly than the case of FIG. 2, since at the time T ₄ before the inlet valve 2 is fully opened reaches about 80% of the target rotational speed N _o, from this point T ₄ Start governor control.

In this modification, since the opening angle of the guide vanes 4 is large, the flow angle α in FIG. 3 is further increased, and accordingly the angle β is reduced, so that the stress α generated in the runner 5 can be further reduced. it can. Further, the time required for the power generation start operation is also reduced.

Next, an embodiment of a method for controlling a hydraulic machine according to the second invention of the present application will be described. When the power generation operation switching command is generated at time T1 as shown in FIG. 5 during the pumping operation, the guide blade 4 is closed to a relatively large predetermined opening degree as shown in FIG. 5B. Guide vane opening degree ag
Is reached at time T4, this opening is maintained.
As shown in FIG. 5 (a), the opening ai of the inlet valve 2 is set at the time T.
At 2, the closing operation is started from the fully open state, and when the opening reaches a small predetermined opening at time T5, the opening is maintained at this predetermined opening.

When the generator motor (not shown) is disconnected from the power system at time T3 as shown in FIG. 5 (d), the runner rotation speed N in the pump direction as shown in FIG. 5 (c). There starts deceleration at the time T ₆ becomes zero, the rotation of the water wheel direction is started. This rotational speed N in the direction of the turbine is at time T ₇
When it is detected that the first predetermined speed has been reached, the inlet valve 2 is further opened to the fully open position as shown in FIG.

The second predetermined speed waterwheel direction of runner rotational speed N is set in advance, for example at the target rotation speed N _o time T _8, which reaches about 80% of, and starts to control the runner rotational speed of the governor, the target adjusting the guide vanes opening a _g such that the rotational speed N _o.

[0029] Figure 6 when runner rotational speed N is zero, i.e., shows the velocity triangle at time T ₆ in FIG. 5, since the peripheral speed of the runner blades 7 is zero, the relative velocity W is absolute velocity V Matches. 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,
Further, since the inlet valve is set to a predetermined small opening degree, the value of the absolute speed V is small. Therefore, the angle β between the direction of the relative velocity W of the pressurized water and the direction of the runner blade 7 becomes significantly smaller than in the prior art, even though the peripheral speed of the runner blade 7 is zero. The applied stress is also greatly reduced.

Also in this embodiment, as in the case of the first invention, the guide blade opening can be set to the no-load opening during the power generation operation. Figure 7 shows a time diagram of a modification of the embodiment of the second invention, the time T ₆ the runner rotational speed N becomes zero
, The opening of the inlet valve 2 is changed. That is,
Inlet valve 2 has a very small opening between the time point T ₅ through T _6, the opening between the time T ₆ through T ₇ are defined larger. As a result, the runner rotation speed N is close to zero,
In particular, the runner blade stress α immediately before the runner rotation speed N becomes zero can be further reduced as shown in FIG.

FIG. 8 shows an embodiment of a hydraulic machine according to the third invention of the present application. 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 blade 4. And the runner 5 is connected to a flow path 9. Thus, the bypass pipe 8 bypasses the guide blade 4 and connects the casing 3 and the flow path 9. A control valve 10 is installed in the bypass pipe 8, and the control valve 10
Opening / closing is controlled by the output of. A rotation speed detector (not shown) is provided on the main shaft 12 and detects the rotation speed of the runner 5. Other configurations are shown in FIG.
0.

The starting of the hydraulic machine is performed as follows. After the inlet valve 1 is fully opened, the opening a _c of the control valve 10 at time T ₁ as shown in FIG. 9 (a) is fully opened. Thereby, the pressurized water passing through the inlet pipe 1, the inlet valve 2, and the casing 3 flows into the flow passage 9 through the bypass pipe 8, and flows out from the flow passage 9 through the runner 5 to the suction pipe 6.
Thus, the runner 5 is rotated in advance by the pressurized water passing through the bypass pipe 8.

Based on the detection output of the rotation speed detector for detecting the rotation speed N of the runner 5, the control device 11 determines the time T when the runner rotation speed N reaches a predetermined value.
_Second , the control valve 10 is fully closed and the guide blades 4 are opened as shown in FIG. 9B to increase the runner rotational speed N to the target rotational speed, that is, the rated rotational speed.

As described above, when the guide blades 4 are opened at the time of starting, the runner 5 is rotated at a predetermined rotation speed in advance.
The runner circumferential speed U is relatively large, and therefore the relative flow is in the direction along the runner blade 7 as compared with the conventional case, and FIG.
As shown in (1), the stress α acting on the runner blade becomes sufficiently small. Further, since the control valve 10 is closed during the steady operation, the water flow passing through the bypass pipe 8 does not disturb the water flow from the guide blade 4. In the above embodiment, the bypass pipe 8 connects the casing 3 and the flow path 9. However, the bypass pipe 8 may communicate the inlet pipe 1 and the flow path 9.

[0035]

As is apparent from the above description, according to the first aspect of the present invention, the guide blade is previously opened to the start opening when the pressurized water is introduced into the runner at the time of power generation. Since the flow angle of the absolute velocity of the pressurized water is large and the opening degree of the inlet valve is small, the absolute velocity is small. Therefore, the angle between the direction of the relative speed of the pressurized water and the direction of the runner blades is significantly smaller than in the past, the stress acting on the runner blades is significantly reduced, and the reduction in fatigue strength of the runner blades is reduced. As a result, the generation of vibration around the runner due to the impact of the water flow can be reduced.

According to the second aspect of the present invention, at the time of the transition from the pumping operation to the power generation starting operation, the flow angle of the absolute velocity of the pressurized water is large because the guide blades are set to the predetermined opening beforehand. Since the inlet valve is set to a predetermined small opening, the absolute speed is small. Therefore, the angle between the direction of the relative speed of the pressurized water and the direction of the runner blades is significantly smaller than in the past, the stress acting on the runner blades is also significantly reduced, and the decrease in the fatigue strength of the runner blades is reduced. As a result, the generation of vibration around the runner due to the impact of the water flow can be reduced.

According to the third aspect of the present invention, when the turbine is started, the runner rotates in advance before the guide blades are opened, and the peripheral speed of the runner is sufficiently high. Flows along the runner blades, the stress acting on the runner blades is greatly reduced, the decrease in the fatigue strength of the runner blades can be reduced, and the generation of vibration around the runners due to the impact of the water flow can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a time chart for explaining a starting method of the embodiment.

FIG. 3 is a speed triangular diagram of a runner blade inlet portion at the time of startup of the embodiment.

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

FIG. 5 is a time chart for explaining one embodiment of a control method for a hydraulic machine according to the second invention of the present application.

FIG. 6 is a speed triangular diagram of a runner blade inlet portion at the time of startup of the embodiment of the second invention.

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

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

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

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

FIG. 11 is a time chart for explaining a conventional power generation starting method of a hydraulic machine.

FIG. 12 is a speed triangular diagram of a runner blade inlet portion during a stationary power generation operation of a conventional hydraulic machine.

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

FIG. 14 is a speed triangular diagram of a runner blade inlet portion during a conventional pumping operation.

FIG. 15 is a speed triangular diagram of a runner blade inlet at the time of power generation startup of a conventional hydraulic machine.

FIG. 16 is a speed triangular diagram of a runner blade inlet at the time of transition from conventional pumping operation to power generation operation.

[Explanation of symbols]

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

Claims (3)

(57) [Claims] 1. A method for starting a hydraulic machine comprising an inlet valve, a movable guide vane and a runner, wherein the guide vane is opened to a predetermined start opening degree, and the opening is performed to the predetermined start opening degree. A step of subsequently opening the inlet valve from a fully closed state to a relatively small predetermined opening degree;
Detecting the rotation speed of the runner while maintaining the same;
Opening the inlet valve to a full opening when the rotation speed detection value of the runner reaches a predetermined value. 2. A control method for a hydraulic machine comprising an inlet valve, a movable guide vane and a runner, and capable of switching between a pumping operation and a power generation operation. A first step of closing, a second step of closing the inlet valve from a fully opened state to a predetermined small opening degree during the first step, and disconnecting the generator motor of the pump turbine from the power system during the second step A third step of detecting the rotation speed of the runner and opening the inlet valve to a full opening when the rotation speed detection value reaches a predetermined value in the rotation direction of the power generation operation. Characteristic control method of hydraulic machine. 3. A hydraulic machine having an inlet pipe, a casing, movable guide vanes and a runner, wherein at least one of the inlet pipe and the casing communicates with a flow path between the guide vanes 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 vanes when the hydraulic machine is started.