KR840001726B1 - Method of controlling punp-turbine - Google Patents

Abstract

A method of controlling a pump-turbine having an S-section in its characteristic curve. The behaviour of thr operation point tracing up the S-section is judged and discriminated through detection of the rotaion speed N of the pumpturbine or the acceleration dN,dt of the same. More specifically, it is judged that the operation point of the pump-turbine is tracing the S-section of the conditions that the acceleration dN/dt is materially negative and that the rotation speed N is greater than a predetermined speed.

Description

Pump aberration control method

1A and 1B are explanatory diagrams of S-characteristics peculiar to a pump aberration.

2A, 2B, 2C, and 2D are explanatory views of a pump aberration control method according to the prior art.

3 is a transient response when the load is cut off of the pump aberration to which the present invention is applied.

4 is a transient response when the load is cut off of the pump aberration to which the present invention is applied.

5 is a schematic diagram of an apparatus for realizing the present invention.

6 is a schematic diagram of an apparatus for implementing the present invention.

7 is a transient response diagram at the time of breaking the load of the pump aberration to which the present invention is applied.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump aberration, and relates to a control method of a high head pump aberration, in which the S-shaped characteristic is the top in a high water running region.

The following references are cited as the technical background of the present invention.

1. U.S. Patent No. 3,452,962 (July 1, 1969),

2. Japanese Patent Publication No. 49-40902 (issued date November 6, 1974),

3. Japanese Patent Laid-Open Publication No. 51-101466 (issued date September 8, 1976),

The following references are cited as applications of the inventors and their successors.

U.S. Patent Application No. 908,202 (filed May 22, 1978) In general, pump aberrations, in particular devices other than runners of high aberration pump aberrations, are designed to exert sufficient centrifugal pump action to obtain high heads during pump operation. .

However, this design adversely affects the aberration operation of the pump aberration. The characteristics of the pump aberration that this design is employed, with a predetermined guide vane opening degree of the rotational speed of the units (單位落差當) in under (開度) (N ₁₎ and a unit free fall per flow (流量) (Q ₁₎ If indicated by the characteristic curve representing the relationship, according to the characteristic curve aberration operating range, with an increase in the N ₁ values Q portion of the that _one value is reduced and, in accordance with the reduction of N ₁ values Q ₁ value is decreasing Has a second part.

In the present specification, the second portion is referred to as an S-shaped characteristic portion, and the characteristics of the pump aberration having this S-shaped characteristic are shown in FIGS. 1A and 1B. In FIG. 1A, the characteristic of the pump aberration is represented by the relationship between the rotational speed N1 _per unit drop and the flow rate Q1 _per unit drop, taking the opening degree of a guide blade as a parameter. On the other hand it becomes as shown in the relationship of the FIG. 1b of the pump aberration characteristics, the number of revolutions per unit free fall by the same parameters (N ₁₎ and per unit of free fall and oak (T _1).

N ₁ , Q ₁ and T ₁ are represented by the following formulas.

In the above formulas, symbols N, Q, H, and T represent the rotation speed, the flow rate, the effective drop and the torque of the pump aberration, respectively. The characteristic curves 1 and 1 'are obtained under the opening degree of a predetermined relatively large guide blade.

The characteristic curves 2 and 2 'are obtained under the opening degree of the guide blade smaller than that.

The characteristic curves 3 and 3 'are obtained under the opening degree of the guide blade smaller than that.

In the adh portion of the characteristic curve 1, the value of Q decreases as the N ₁ decreases. As described above, this curved portion adh is referred to herein as an S-shaped characteristic portion.

Further, the curved portion b-e-i is the S-shaped characteristic portion of the characteristic curve 2, and the curved portion c-f-j is the S-shaped characteristic portion of the characteristic curve 3.

As can be clearly seen in FIG. 1A, the S-shaped characteristic portion adh of the characteristic curve 1 is longer than the S-shaped characteristic portion (bei) of the characteristic curve 2, and the S-shaped characteristic portion of the characteristic curve 2 (bei) is longer than the S-shaped characteristic part (cfj) of the characteristic curve (3). This means that the smaller the opening degree of the guide blade is, the shorter the length of the S-shaped characteristic portion is.

Also in FIG. 1B as in FIG. 1A, the curved portions a'-d'-h ', (b'-e'-i'), and (c'-f'-j ') are each characterized by the characteristic curve (1). S-characteristic part of '), (2'), (3 ').

FIG. 1b is closely related to FIG. 1a.

For example, the point (X) that satisfies _{Q 1 = Q 1X, N 1} = N 1X on claim 1a-degree curve 3 corresponds to a "point (X on) a 1b-degree curve (3) '. The point X 'satisfies T ₁ = T _1X , N ₁ = N _1X (= N _1X ). In Fig. 1a, points (a), (b), (c), (d), (e), (f), (h), (i), and (j) are respectively shown in Fig. 1b. Corresponds to points a ', (b'), (c '), (d'), (e '), (f'), (h '), (i') and (j ').

Curve n _г is a no-load flow curve. The intersections (α), (β), and (г) between curves (1), (2), (3) and curve (n _г ) and curves (1 '), (2'), (3 ') and Corresponds to the intersections α ', (β') and (г ') with the straight line T ₁ = 0. FIG.

Next, the aberration operation (power generation operation) of the pump aberration will be described with reference to characteristic curves 1 and 1. FIG. The characteristics corresponding to the characteristic curves 1 and 1 'as described above are obtained when the opening degree of the guide blade is made a relatively large value. Generally, the aberration operation of the pump aberration is performed at the upper portion of the characteristic curve 1, that is, at the upper portion of the S-shaped characteristic portion adh. However, if the load on the pump aberration is suddenly lost, for example, since the rotation speed N of the pump aberration rapidly increases, the value of N ₁ also increases rapidly. In this way, the VJA aberration starts to operate in the S-characteristic part. During operation in the S-shaped portion, if the value of N ₁ decreases due to the decrease in the rotation speed N of the pump aberration, the value of Q ₁ also decreases. Assuming that the value of H is constant, decreasing the value of Q ₁ means that the flow rate Q of the pump aberration correspondingly decreases. In reality, the value of H, that is, the water head difference at the inlet of the pump aberration coupled to the hydraulic steel pipe and the outlet of the pump aberration coupled to the draft tube, increases simultaneously with the decrease in the flow rate Q.

In this way, once the value of N ₁ decreases, the flow rate Q decreases, so that the decrease in the flow rate Q causes an increase in the effective drop H of the pump aberration. This increase in effective drop H also results in a decrease in N _{1 and} a decrease in H ₁ also results in a decrease in Q ₁ .

When in this way to one end of operation of the S-curve characteristic part begins Q ₁ and N ₁ is the S-characteristic part Q ₁ decrease direction, that is, going moved in the direction of the point h from the point a to the accelerated, and continuously decreases do. It can be understood that Q ₁ and N ₁ decrease acceleration and successively as in the noble control circuit.

When the driving point of the pump aberration moves the S-characteristic part from the point (a) to the point (h), the above phenomenon is gradually alleviated as in the negative feedback control circuit. Is moved from Q ₁ increasing direction, that is, from point h to point a. Moving the S-characteristic part in the reverse direction is also performed in the same manner as the return control circuit.

While the pump aberration is operated in the S-shaped portion, the above reciprocating motion is repeated almost continuously. As described earlier, such operation is undesirable.

This is because it causes strange hydraulic pressure change in each waterway system of hydroelectric power plant, which causes violent water hammer and sometimes sedimentation of water column.

It should be noted that this adverse effect of the operation on the S-shaped portion decreases as the length of the S-shaped portion decreases.

For example, if the pump aberration is driven in accordance with the characteristic curve 2 having the shorter S-shaped part b-e-i by opening the guide blade smaller, the adverse effect of the S-shaped property is reduced.

The operation of the pump aberration in the S-characteristic part also adversely affects the torque T of the pump aberration. As the value of N ₁ decreases in the S-characteristic portion, the value of T ₁ also decreases as shown in FIG. Here again, points (a) and (h) on the characteristic curve 1 shown in FIG. 1a correspond to points a 'and (h') on the characteristic curve 1 'shown in FIG. 1b, respectively. You must be careful.

Assuming that the effective drop H is constant, a decrease in T _{1 means} a decrease in the pump aberration torque T. On the other hand, it is apparent that the reduction in the pump aberration torque T causes the reduction in the pump aberration rotation speed N.

When the pump aberration speed N decreases, N ₁ decreases correspondingly, and then T ₁ also decreases.

In reality, since the effective drop H increases as described above, the acceleration tendency becomes more severe.

In this way, the pump aberration moves the characteristic curve 1 'from the point a' to the point h 'while the characteristic curve 1 is moved in the Q ₁ reduction direction. The moving direction is the same as that of the positive feedback control circuit. Then, when the direction of moving the S-shaped characteristic portion is reversed, the characteristic curve 1 'is moved in the direction of the point a' from the point h '.

Torque changes as evident above are not beneficial.

2A to 2D are schematic diagrams showing a conventional example of the guide vane control method at the time of blocking the pump aberration load. In these figures, the prior art is schematically shown in accordance with the relationship between the opening of the guide vane and the passage of time after the load is interrupted. If there is a load interruption, the guide vanes are normally closed by the action of the governor of the pump aberration.

In the method of FIG. 2A, the governor stops closing the guide vanes for a predetermined time after the load is interrupted. In more detail, the guide vanes are held at a certain opening for a certain time, and then are rapidly closed. In the method of FIG. 2B, the guide vanes slowly open initially and then close rapidly.

These methods have the following drawbacks.

Even if the load is interrupted, the operating state of the pump aberration is not included in the S-shaped part until the rotation speed N ₁ per unit free fall reaches the point (a) of FIG. 1a.

Operation in the S-shaped portion starts after a certain time has elapsed from the load shedding. In contrast to the methods of FIGS. 2A and 2B, it is preferable that the guide vane is rapidly closed for a predetermined time from the load interruption to entering the S-shaped part.

This is because, by this rapid closing operation, the pump aberration characteristic shifts in the direction to alleviate the adverse effect caused by the S-shaped portion. For example, by closing the guide blade (that is, reducing the guide blade opening degree), the characteristic of the pump aberration shown in the characteristic curve 1 of FIG. 1a shifts to the characteristic shown in the characteristic curve 2. By this transition, since the characteristic curve 2 has an S-shaped characteristic part smaller than the characteristic curve 1, the adverse effect which becomes a problem is alleviated. In this respect, the method of FIGS. 2A and 2B is not preferable.

It should also be noted that when the pump aberration is operating while moving the S-shaped part in the direction of decreasing Q ₁ , the rapid guiding blade should be closed.

This is because Q ₁ and N ₁ decrease due to the rapid closure, and the effect of the S-shaped property is more severe.

The methods of FIGS. 2A and 2B are dangerous because the timing of the rapid closure of the guide blades is unclear. If the pump aberration is to close the guide blades rapidly when the S-shaped part is moving in the direction of increasing flow, these methods are effective to some extent.

However, if the S-characteristic part is moved in the direction of flow rate reduction, attempting to perform the above-mentioned rapid closing causes the adverse effect of the S-characteristic part to be very severe.

Thus, as described above, once the opening of the guide blade stops above a predetermined value, once entering the S-shaped part, it has a constant period almost permanently and moves the S-shaped part in the direction of decreasing Q ₁ immediately in the increasing direction. Return and move in the decreasing direction. That is, the opportunity to immediately close the guide vanes as a pump aberration and immediately perform shell removal in the operation of the S-shaped portion is not limited to the predetermined time after the load interruption, but appears repeatedly. In all of these opportunities, an abnormal hydraulic pressure change must be prevented.

The method of FIG. 2C is disclosed in Japanese Patent Publication No. 49-40902.

In this method, after an unexpected load interruption, the guide vanes are first closed rapidly and then closed slowly in the operating region where the flow rate decreases significantly with increasing pump aberration speed, and then closes rapidly.

This method has the drawback that the timing of the last rapid closure is not clear.

If the rapid closing is performed in an operating state in which the S-characteristic portion is moved in the Q ₁ reduction direction, the above-mentioned dangerous situation occurs. In the case of a plurality of pump aberrations coupled in parallel to a common hydraulic steel tube and a common draft tube, the operation of another pump aberration is affected by the operation of one pump aberration.

In this case, even if there is no load interruption, there is a possibility that some pumps and aberrations are operated near the S-shaped part under the influence of water hammer caused by other pump aberrations. If the initial rapid closing in FIG. 2C is performed for the pump aberration operating near the S-characteristic portion as described above, when the pump aberration is shifting the S-characteristic in the Q ₁ decreasing direction. There is a risk of closure.

In addition, the pump aberration will move the S-shaped portion with the Q ₁ decrease direction and increase direction even while the guide vanes are gradually closed on the way, so it is a serious problem at which point the last rapid guide vane is closed. Does not provide any provisions.

In the method of FIG. 2D, the closing operation of the guide blade is performed in two stages. This method also has drawbacks because the timing of closing operation is not clear.

As described above, the prior art has a common point that the determination of the closing operation timing of the guide blade is not made in consideration of the S-shape characteristic.

In order to avoid unfavorable abnormal hydraulic pressure fluctuations, it is necessary to perform the rapid closing action of the guide vanes while the pump aberration is moving the S-characteristic part in the direction of Q ₁ reduction. In one must not operate the guide vanes as long as the movement of the S-characteristic part Q ₁ increasing direction.

The present inventors have discovered a guide wing control method in which the S-characteristics described above are analyzed to obtain a preferable result. The method is already filed in the United States. The application is described in the section "List of Prior Applications Cited at the Beginning" of this specification.

The above-described guide vane control method is described next.

First, the inventors have found that it is effective to temporarily open this during closing operation of the guide blades in order to prevent the adverse effect of the S-shape due to the load interruption. This temporary opening operation may be performed when it is detected that the guide vane is closed to a predetermined opening degree.

Alternatively, this temporary opening operation may be performed after a predetermined time elapses after the load is cut off.

In order not to increase the adverse effect of moving the S-shaped characteristic portion in the direction of decreasing Q _1, it is necessary not to close the guide vanes rapidly at least. However, more preferably, the opening operation of the guide blade is performed when detecting that the S-shaped characteristic portion is moved in the Q ₁ reduction direction.

Figure 1a and the second 1b when the operation of the pump aberrations as will be understood from the S-curve characteristic is performed to write the road section the relationship of ∂Q ₁ / N∂ _1> 0 and ∂T ₁ / ∂N _1> 0 is chungjon have.

The relationship between dN ₁ / dt <0 and dQ ₁ / dt <0 is satisfied when the S-shaped characteristic portion is moved in the Q ₁ reduction direction.

Where t is time. When dQ ₁ / dt <0, the relationship of dP / dt> 0 is established. (P pressure of the steel pipe)

In this way, the operation detection of the pump aberration in the S-characteristic portion can be performed by using the above-described many relationships. More specifically, the detection that the operation state of the pump aberration is moving the S-shaped characteristic portion in the Q ₁ reduction direction can be performed by detecting that the following three conditions are satisfied.

(A) dN ₁ / dt <0 and dQ ₁ / dt <0

(B) dN ₁ / dt <0 and dP / dt> 0

(C) dT ₁ / dt <0 and dN ₁ / dt <0

In order to perform accurate detection of this pump aberration operation state, it is preferable to detect that any of the conditions A to C described above is completely satisfied. However, from the object of the present invention, conditions A to C can be changed from the following conditions A 'to C'.

(A ') Value close to dN ₁ / dt <0 and Value close to dQ ₁ / dt <0

(B ') values close to dN ₁ / dt <0 and values close to dP / dt> 0

(C ') Value close to dT ₁ / dt <0 and Value close to dN ₁ / dt <0

The expression d ² N / dt ² <0 described below can also be changed in accordance with a value close to d ² N / dt ² <0.

The inventors believe that even when dN / dt, dQ / dt and dT / dt are substituted with dN ₁ / dt, dQ ₁ / dt and dT ₁ / dt, respectively, the detection can be made substantially accurate.

This substitution is obtained on the assumption that the effective drop in pump aberration is substantially constant. It is also possible to detect that the pump aberration is operating in the S-characteristic part by other factors.

For example, it is also possible by detecting that the relationship between each factor described in any of the following items is satisfied.

(1) Rotation speed of pump aberration (N), effective drop of pump aberration (H), output of pump aberration or torque of pump aberration and opening degree of guide vane (Y)

(2) H, pump aberration output and Y (detection by these factors is possible, for example, when the pump aberration is systematically fed in, where N is substantially constant).

(3) Output of pump aberration and, if necessary, Y (the same conditions as in (2) above).

(4) ∂T ₁ / ∂N ₁ and if necessary, Y

(5) dT / dt, dN ₁ / dt and Y if necessary

(6) dT / dt, dH / dt and, if necessary, Y (same conditions as in item (2) above).

(7) N, H, Q and Y

(8) H, Q and Y (the same conditions as in item (2) above).

(9) ∂Q ₁ / ∂N ₁ and Y if necessary

(10) dQ / dt, dN ₁ / dt and Y if necessary

(11) dQ / dt, dH / dt and, if necessary, Y (same conditions as in item (2) above).

(12) N, H and Y (when the output of pump aberration or Q is substantially constant)

(13) d ² N / dt ² , dN / dt and Y if necessary

As described above, it is possible to detect that the pump aberration is driving the S-characteristic part in many ways. However, it is preferable to detect only the rotation speed N of the pump aberration as in item 13.

This is because the change in the rotational speed of the pump aberration during operation is gentle and the change in the rotational speed is good and can be easily detected. In general, the detection of H and T is not performed with high precision.

The Applicant uses two factors, dN / dt <0 and d ² N / dt, to detect that the driving point of the pump aberration is moving in the direction of reduction of the S-characteristic part using the factor of item (13). It was found that it is good to detect that the condition of ² <0 is satisfied.

This invention is made | formed in view of the said situation, The objective is to reduce the fluctuation | variation of water pressure quickly and reliably. That is, the feature of the present invention is a method of closing the guide vane which closes the flowing water by rapidly closing the guide vane at the same time as the occurrence of a sudden load fluctuation, and then renovating it during the closing or closing the vane. In this case, the set value of the closing start point for rapidly closing the second guide vane is set above the rated rotational speed, and it is rapidly detected by detecting that the rotational speed of the pump aberration which rises due to the load variation is smaller than the set value. To close the pump aberration control method.

An embodiment of the present invention will be described with reference to FIG. Fig. 1 shows the stroke change (A) of the guide vane servomotor after the load interruption occurs at time t ₀ , the change in the rotation speed of the pump aberration (B), the change in the water pressure (C) upstream of the pump aberration (steel pipe), and the pump aberration. It shows the water pressure change (D) on the downstream side of the suction tube.

In FIG. 7, the region ∂A satisfies the conditions of dN / dt <0 and d ² N / dt ² <0, so that the driving point of the pump aberration moves the S-shaped characteristic portion in the flow reduction direction in this region. As a result of the observation, the operating point of the pump aberration moves the S-characteristic part in the flow decreasing direction, in which the rotational speed N is lowering and the rotational speed N is considerably higher than the rated rotational speed N ₀ . Able to know.

이다.This observation shows that pump aberrations are subject to both substantial and simultaneous satisfaction of dN / dt <0, N> Na (where Na is higher than the rated rotational speed (N ₀ ) as shown in Fig. 7). It detects that the operation point is moving the S-characteristic part in the direction of decreasing the flow rate. When N <Na, the guide vane is rapidly closed to block the flowing water. The point that this guide blade closes rapidly

to be.

In the control method shown in FIG. 4 after the load shedding a certain amount of time (t ₀ ~ t ₁₎ or close operation rapidly by the guide vanes is closed to a predetermined opening degree and, after t ₁ is thus close operation to the delay speed.

에 상당)에서 다시 안내날개의 급속한 폐동작을 행한다. 이 경우는 제 도의 과우와는 달리 안내날개를 개동작시킬 필요가 없으므로

점을 확실하게 검출할 수 있다면 좋다(이로써 최후의 급속폐 동작을 행하여 수압의 동요를 일거에 없앤다). 제 도의 경우는 dN/dt<0, N>Na의 조합으로 δB의 범위를 검출하여 이것이 종료된 시점, 즉, N<Na로 되면 제 도와 같이 안내날개를 급속하게 폐쇄하여 흐르는 물을 차단한다. 제 도는 제 도에 나타낸 안내날개의 조작을 실현하기 위한 장치를 나타낸 것이다.And when the movement of the S-shaped part in the direction of the flow reduction ends (the stroke change curve of the motor

), The rapid closing motion of the guide blades is performed again. In this case, unlike in the case of the practice, the guide vanes do not need to be opened.

If a point can be detected reliably, it will be good. In the case of FIG. 6, the range of δB is detected by a combination of dN / dt <0, N> Na. When this is finished, that is, when N <Na, the guide vane is rapidly closed to block the flowing water. FIG. Shows an apparatus for realizing the operation of the guide blade shown in FIG.

That is, the solenoid SOL connected to the positive DC power supply P _E and the negative DC power supply N _E has two mechanical switches, namely, the speed switch SSW (N> Na). When all three switches are turned on, ON, the acceleration switch ASW (ON under the condition of dN / dt <0), and the low power switch LSW (ON by detecting the generator load loss) are excited.

Then, the valve 6 is switched so that the pressure oil PO ₁ supplied from the pressure oil tank acts as the lower side of the stopper piston 11.

The stopper piston 11 is then pushed up to the top of the cylinder 10. The lever 8 then rotates around the point 7 and lifts the stopper plate 9 coupled by the plunger 13 of the main back pressure valve 14 and the piston of the relay servo motor. .

As a result, the plunger 13 which has been operated downward by the discharge of the control hydraulic pressure 24 and the pressure oil PO ₂ is forcibly moved under the support of the speed governor (not shown).

Thus, the main back pressure valve 14 communicates the pressure oil PO ₃ supplied from the pressure oil tank to the pipe line 19 while communicating the pipe line 20 to the oil pipe line 23.

Thus, the piston 22 of the guide vane servo motor 21 operates in the open direction.

After that, when N <Na, the solenoid SOL is reset so that the SSW is turned off, the stopper piston 11 is lowered, and the lever 8 is pulled down completely, so that the control of the guide vane servomotor 21 is controlled. It is left to control of the control oil pressure 24 provided to the base of the relay servomotor piston 1 which drives the main back pressure valve plunger 13. At this time, since the rotation speed N is considerably higher than the rated value N ₀ , the control of the governor (not shown) connects the control hydraulic pressure 24 to the discharge side. Therefore, the relay servo motor piston 18 is completely pushed down.

That is, the plunger 13 of the main back pressure valve is lowered to a position limited by the stop nuts 16-1 and 16-2 set in advance.

점이하의 급속한 폐동작이 실현된다. 그리고 제 도에 있어서, 17-1 및 17-2는 스톱너트, 15-1 및 15-2는 볼트이다.Thus, the hydraulic oil is switched to the bay, so that the servomotor piston 22 of the guide blade moves rapidly in the closed direction. In other words,

Rapid closing operation below the point is realized. And 17-1 and 17-2 are stop nuts and 15-1 and 15-2 are bolts.

Next, another embodiment of the present invention will be described with reference to FIG. The hydraulic pressure of the servomotor change (A), rotational speed change (B) of the guide blade after the load interruption time point t ₀ of the pump aberration as shown in FIGS. 3 and 4 of FIG. The change (C) and the water pressure change (D) on the downstream side (absorber tube) are shown.

As can be understood from the figure, the driving point of the pump aberration is moved to the direction of flow rate reduction after the load is cut off when the rotation speed of the pump aberration rises once and then descends to reach the rated rotation (N ₀ ). Thus, a device for storing one rotational speed higher than the first predetermined value N ₁₀ is provided, and then a device for detecting that the rotational speed has fallen below the second predetermined value N ₂₀ is provided.

점)을 검출하는 것이다.Then, the timing of the problem is provided that the detection device of N ₂₀ is operated after the storage device of N ₁₀ is operated.

Point).

6 shows an apparatus for realizing the embodiment of FIG. In FIG. 6, the same part as FIG. 5 attaches | subjects the same code | symbol.

점), 접점(29)(Y<Ya일때 온하는 접점)이 온하여 릴레이(25)가 온한다. 릴레이(25)는 자체유지회로(25a)가 있기 때문에 그 후는 온 그대로이며, 밸브(6)의 솔레노이드(SOL)를 오프시킨다.(이 시점에서의 접점(26b)은 오프상태에 있다).When the load is cut off, the contact point 32 is turned on, i.e., in a conducting state, and then when the guide blade opening degree Y becomes smaller than the predetermined opening degree Ya (Fig. 7).

Point), the contact point 29 (contact point turning on when Y <Ya) turns on and the relay 25 turns on. Since the relay 25 has its own holding circuit 25a, it remains on after that and turns off the solenoid SOL of the valve 6. (At this time, the contact 26b is in the off state).

On the other hand, when the rotation speed N of the pump aberration rises to N> N ₁₀ (where N ₁₀ is a predetermined rotation speed) by the load interruption, the contact 31 (contact point turning on when N> N ₁₀ ) turns on. Then, it is also remembered that the relay 27 having its own holding circuit is turned on so that the rotation speed N increases once.

End can speed is lowered in the pump aberration predetermined rotation of the 2 (N ₂₀₎ is smaller than the contact point (30) (N <N contacts ₂₀ when on) contact point (27b of the relay 27 which is previously turned on by the on- ), The relay 26 is turned on.

점에서

점까지의 사이에 오프되어 있게된다.Then, the contact 26b on the solenoid SOL circuit, which has been off, is turned on so that the solenoid SOL is returned to the on state again. That is, the solenoid SOL is shown in FIG.

In terms of

It is off between the points.

Thus, the valve 6 is switched therebetween, so that the pressure oil acts as the lower side of the stopper piston 11, so that the stopper piston 11 is pushed up to the upper end.

Then, the stopper plate 9 directly connected to the main back pressure valve plunger 13 is lifted by the lever 8 so that the plunger 13 is operated upward, so that the guide vane is gently closed because it is restricted from the downward operation. .

Then, when N <N ₂₀ , the solenoid SOL is turned on again as described above, the stopper piston 11 is lowered, and the lever 8 is pulled out completely downward. It is left to control of the control hydraulic pressure 24 given to the base of the relay servo motor piston 18 which drives the plunger of a valve.

At this time, since the rotation speed N is considerably higher than the rated value N ₀ , the control part of the governor (not shown) connects the control hydraulic pressure 24 to the oil supply side to completely push down the piston 18 of the relay servo motor. . That is, the plunger 13 of the water back pressure valve is lowered to a position limited by the preset stop nuts 16-1 and 16-2.

Thus, the hydraulic oil is completely switched in the closed direction so that the servo motor piston 22 of the guide blade moves rapidly in the closed direction. In this device, N ₂₀ <N ₁₀ is set.

As another application example of the present embodiment, it is considered that the degree can be increased by combining the opening switch of the guide vane with each speed switch so as to select the first and second predetermined rotation speeds according to the load value.

As can be understood from the above description, the effect of the present embodiment is to detect the subtle timing when moving the S-characteristic by only a combination of mechanical speed switches, and to achieve the object of the present invention with a simple and high reliability.

According to the present invention, the point for closing the second guide vane rapidly can be set, so that the hydraulic pressure fluctuation can be reduced quickly and reliably.

Claims (1)

In the method of closing the guide vane, the guide vane is rapidly closed at the same time as the occurrence of sudden load fluctuation, and after the remodeling is completed during the closing or closing, and the water flows by closing the guide vane. The pump aberration control method characterized in that the set value of the closing start point to close the valve is set higher than the rated rotational speed and closes rapidly by detecting that the rotational speed of the pump aberration raised by the load fluctuation is smaller than the set value. .

Images