JPH09287547A - Operation method of high specific speed reversible pump-turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent water thrust from abnormally increasing by closing a guide vane quickly directly after interception and slowly after a first peak value of rotating speed, so that at full load interception, first and second peak values in a specific relation appear in water pressure of a pipe line on the upper stream side respectively before the first peak value of a runner rotating speed and directly after exceeding it. SOLUTION: At full load interception, the opening of a guide vane is controlled so that a first peak value Ha appearing on the pipe line water pressure on the upper stream side before rotating speed of a runner 1 becomes the first maximum rotating speed Np, and a second peak value Hb appearing on the process in which rotating speed of the runner 1 falls after the maximum value Np are in relation of Ha≈Hb or Ha>Hb. For controlling in this way, at first the opening of the guide vane is quickly closed before rotating speed of the runner 1 is raised by load interception and reached to the first maximum rotating speed Np, so as to restrain the rising width itself of rotating speed, and after reaching the first maximum rotating speed Np, it is closed at lower speed than the speed directly after interception, and hence irregular pulsation of S-shaped characteristic is restrained at minimum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump turbine, and more particularly to a high specific speed pump turbine having a product of (specific speed during operation of the turbine [m-KW base unit]) and (square root of maximum effective head [m]) of 2450 or more. .

[0002]

2. Description of the Related Art In a pumped storage power plant, a power generation system is often constructed by using a plurality of pump turbines. An example of this will be described with reference to the schematic view of FIG. In FIG.
One upper pond side pipeline 102 is connected to the upper pond 101, and further the first to third upper pond side branch pipelines 104, 105, 106 are branched from the branch portion 103 on the upper pond side 102, and the lower ends thereof. First to third pump turbines 107, 108, 10 respectively
9 is connected. The pump turbines 107 to 109 are connected to the lower pond 110 via the lower reservoir side pipelines 111, 112, 113, respectively, and the upper reservoir 101 to the pump turbine 10 are connected.
Water is supplied to the 7 to 109 side to operate the water turbine, and Shimoike 1
Pump water is pumped from 10 by pump turbines 107 to 109 to pump water to the side of the upper pond 101.

Generally, pump turbines, especially runners and other equipment of high-lift pump turbines, are designed to exert a sufficient centrifugal pump action in order to obtain a high lift during pump operation. However, such a design has a problem in that, when the pump turbine is operated by a water turbine, an unfavorable characteristic called S-characteristic, which will be described later, cannot be avoided. That is, the characteristics of the pump turbine used in this design are shown by a characteristic curve showing the relationship between the number of revolutions per unit head [N ₁ ] and the flow rate per unit head [Q ₁ ] under a predetermined guide vane opening. In this case, this characteristic curve shows that in the turbine operating region, the _{first part in which} the value of Q ₁ decreases with the increase of the value of N _1
A second part in which the value of Q ₁ decreases with a decrease in the value of ₁ . For convenience of explanation, in the present specification, the second portion is referred to as an S-shaped characteristic portion.
Further, the characteristics of the pump turbine in the S-characteristic portion will be referred to as S-characteristics hereinafter. In hydraulic turbine operation in the S-shaped characteristic portion, the torque per unit head [T ₁ ] also decreases as the number of revolutions per unit head [N ₁ ] decreases.

Normally, the turbine operation of the pump turbine is performed in the first part. However, due to load shedding or load reduction, the number of rotations per unit head [N ₁ ]
If the pump water rapidly increases,
It will be operated in the character part. When the operation in the S-shaped characteristic portion is started, the operating point of the pump turbine follows the S-shaped characteristic portion from one end to the other end, and first, the flow rate per unit head [Q ₁ ] and the number of revolutions per unit head [ N ₁ ]
Decrease. Then, this time, Q ₁ and N ₁ increase while tracing the S-shaped characteristic portion in the opposite direction so that the pendulum turns back. S
This reciprocation in the character portion continues almost permanently as long as the guide vane opening remains above a predetermined value, and does not end unless special measures are taken. During this time, the torque [T ₁ ] per unit head also repeats a decrease and an increase.

It is desirable that the pump turbine be operated while avoiding the S-shaped characteristic portion as much as possible. Because S
As in the case of the pump turbine main body, the operation in the character-shaped part causes abnormal water pressure fluctuations including large water pressure rise and water pressure drop in the penstock and draft tube, and as a result, it may even lead to underwater separation. This is because it is difficult to grasp in advance because the timing of plunging into the S-shaped characteristic part is influenced by other units that share the waterway. The above-mentioned load shedding, for example, when the generator connected to the pump turbine opens the circuit breaker or an accident occurs in equipment between the generator such as the transformer and the power system, causing the generator to lose its load. It occurs when you do. Also note that the water hammer is particularly violent if the penstock or draft tube or both are long.

The characteristics of the pump turbine having the S-shaped characteristic in the turbine operating region are shown in FIGS. 6 (a) and 6 (b). In FIG. 6 (a), the characteristics of the pump turbine are shown as a relationship between the number of revolutions per unit head [N ₁ ] and the flow rate per unit head [Q ₁ ] using the guide vane opening as a parameter. . On the other hand, in the same figure (b), the characteristics of the pump turbine are shown as the relationship between the number of revolutions per unit head [N ₁ ] and the torque per unit head [T ₁ ] with the same parameters. N ₁ , Q ₁ and T ₁ are expressed by the following equations.

N ₁ = N / √H Q ₁ = Q / √H T ₁ = T / H In the above equation, the symbols N, Q, H and T are the rotational speed, flow rate, effective head and torque of the pump turbine, respectively. Indicates.

The characteristic curves CH1 and CH1 'are obtained under a predetermined relatively large guide vane opening, and the characteristic curve CH1
2 and CH2 'are obtained under a smaller guide vane opening, and the characteristic curves CH3 and CH3' are obtained under a smaller guide vane opening.

In the a-d-h part of the characteristic curve CH1, the value of Q ₁ decreases as N ₁ decreases. As described above, in the present specification, this curve portion a-d-h is referred to as S
It is called the character characteristic part. Similarly, the curved portion b-e-i
Is the S-shaped characteristic portion of the characteristic curve CH2, and the curved portion c-
f-j is the S-shaped characteristic portion of the characteristic curve CH3. As can be seen at a glance, the S-shaped characteristic portion a of the characteristic curve CH1
-D-h is the S-shaped characteristic portion b-e-i of the characteristic curve CH2.
Longer, S-shaped characteristic portion b-e-i of the characteristic curve CH2
Is longer than the S-shaped characteristic portion c-f-j of the characteristic curve CH3. This means that the length of the S-shaped characteristic portion becomes shorter as the guide vane opening becomes smaller.

As in FIG. 6 (a), FIG. 6 (b)
Also in the curve portions a'-d'-h ', b'-e'-
i ′ and c′-f′-j ′ are characteristic curves CH, respectively.
It is the S-shaped characteristic portion of 1 ', CH2' and CH3 '.
FIG. 6B has a close relationship with FIG. 6A. For example, the point x on the curve of FIG. 6A that satisfies Q ₁ = Q ₁ x and N ₁ = N ₁ x is the point x ′ on the characteristic curve CH 3 ′ of FIG. 6B.
It corresponds to. The point x ′ is T ₁ = T ₁ x ′, N ₁ = N
It is a point that satisfies ₁ x '(= N ₁ x). Similarly, FIG.
Points a, b, c, d, e, f, g, h, i and j in FIG. 6B are points a ′, b ′, c ′,
It corresponds to d ', e', f ', g', h ', i'and j'.

The curve nr is an unloaded flow rate curve. The intersections α, β, γ between the curves CH1, 2, 3 and the curve nr correspond to the intersections α ′, β ′, γ ′ between the curves CH1 ′, 2 ′, 3 ′ and the straight line T ₁ = 0, respectively. ing.

Next, the turbine operation (power generation operation) of the pump turbine will be described with reference to the characteristic curves CH1 and CH1 '. As described above, the characteristics corresponding to the characteristic curves CH1 and CH1 ′ are obtained when the guide vane opening is set to a relatively large value. Normally, the turbine operation of the pump turbine is performed in the upper portion of the characteristic curve CH1, that is, in the curved portion above the S-shaped characteristic portion a-d-h. However, for example, when the load applied to the pump turbine is suddenly lost, the rotation speed [N] of the pump turbine rapidly increases,
The value of N ₁ also increases sharply. Thus, the pump turbine S
The operation in the character part starts.

During the operation in the S-shaped characteristic portion, when the value of N ₁ decreases due to the decrease of the rotational speed [N] of the pump turbine, the value of Q ₁ also decreases. Assuming that the value of H is constant, a decrease in the value of Q ₁ means a corresponding decrease in the pump turbine flow rate [Q]. In reality, H
Value, that is, the head difference between the pump turbine inlet connected to the penstock and the pump turbine outlet connected to the draft tube increases at the same time as the flow rate Q decreases. In this way,
Once the value of N ₁ decreases, the flow rate Q decreases, and the decrease of the flow rate Q causes the effective head H of the pump turbine to increase. This increase in effective head H further resulted in a reduction of N _1, N ₁
The reduction of Q ₁ also leads to the reduction of Q ₁ . In this way,
Once the operation in the S-shaped portion starts, Q ₁ and N ₁
Indicates the S-shaped characteristic portion in the direction of decreasing Q ₁ , that is, from point a to point d
As it goes in the direction of, the acceleration decreases continuously. Q ₁ and N ₁ decrease at an accelerating and continuous level, as in the positive feedback control circuit. When the operating point of the pump turbine finishes tracing the S-shaped characteristic portion from the point a to the point h, the above phenomenon is gradually alleviated in the same manner as in the negative feedback control circuit, and thereafter, the phenomenon is reversed and the S-shaped characteristic portion is changed to Q. _The direction of increase is ₁ , that is, the point h is traced to the point a. Tracing the S-shaped characteristic portion in the reverse direction is also performed in the same manner as the arrow-shaped positive feedback control circuit.

While the pump turbine is operating in the S-shaped portion, the above reciprocating motion is repeated almost permanently. As mentioned above, such operation is not desirable.
The reason for this is that an abnormal water pressure change is caused in each channel system of the hydroelectric power plant, and the water pressure change causes a drastic water hammer and sometimes even an underwater separation phenomenon.

Since such an adverse effect due to the operation in the S-shaped characteristic portion is reduced as described above when the length of the S-shaped characteristic portion is shortened, for example, the guide vane opening is made smaller to shorten the S-characteristic portion. If the pump turbine is operated in accordance with the characteristic curve 2 having the characteristic portion b-e-i, the adverse effects associated with the S-shaped characteristic are reduced.

The operation of the pump turbine in the S-shaped characteristic portion also adversely affects the torque T of the pump turbine. When the value of N ₁ decreases in the S-shaped characteristic portion, the value of T ₁ decreases as shown in FIG. 6 (b).

Assuming that the effective head H is constant, T
A decrease of ₁ means a decrease in pump turbine torque T. Further, the decrease in the pump turbine torque T is due to the pump turbine rotation speed N.
It is clear that this leads to a decrease in When the pump turbine speed N decreases, N ₁ decreases correspondingly, and then T
₁ will be further reduced. In reality, since the effective head H is increasing during this period as described above, this acceleration tendency becomes stronger. In this way, the pump turbine during follow a characteristic curve CH1 to Q ₁ decreasing direction, at the same time characteristic curve CH
1'is traced from the point a'to the point h '. The tracing method is the same as in the case of the positive feedback control circuit. After that, when the direction following the S-shaped characteristic portion is reversed, the characteristic curve C
H1 'will be traced from the point h'to the point a'. Obviously, such a torque change is not preferable in terms of characteristics.

By the way, at present, pump turbines are becoming faster and larger in capacity, and the specific speed is being made higher at any pump head. K value defined by the product of (-KW unit basis)) and (square root of maximum effective head [m]) is gradually increasing. FIG. 7 is a cross-sectional view showing the main part of the runner showing the difference in runner shape between the case where the specific speed Ns is high (a) and the case where the specific speed Ns is low (b). In the figure, D ₀ is the runner inlet diameter, and Dseal is the runner seal diameter. However, as the specific speed is increased in this way, the water thrust generated at the time of load shedding tends to increase as shown in FIG. In particular, when the upper pond side pipe line 102 is branched as shown in FIG. 5 and the upper pond side pipe line 102 beyond the branch point 103 is shared with other pump turbines, a method for closing the guide vanes is If not appropriate, the increase in water thrust when shutting off multiple units simultaneously becomes serious.

The specific speed during operation of the water turbine is defined below.

Ns = No × (P ^1/2 / H ^5/4 ) where P is the rated output [KW] and No is the rated rotation speed [rpm].

[0021]

Now, let us consider the pump turbine and the factors causing the downward water thrust generated in the pump turbine.

FIG. 9 is a schematic view of a pump turbine, in which a runner 1 is supported by a main shaft 2 at its center and rotatably housed in a runner chamber cover 3. The runner chamber cover 3 is connected to the draft tube 4 at the center lower end of the runner 2, and is connected to the guide valve side at the outer peripheral portion of the runner 2. The runner chamber cover 3 includes an upper cover 3a and a lower cover 3b. An upper seal portion 5 and an upper seal constituent portion 6 of the runner are provided between the upper side and the upper cover 3a of the runner 2, respectively. A lower seal portion 7 of the runner and a lower seal component portion 8 of the lower cover are provided between the lower side of 2 and the lower cover 3b, respectively. Similarly, the outer periphery of the runner 1 and the upper cover 3
The runner outer peripheral upper side seal portion 9 is provided between the lower cover 3 and
A runner outer peripheral lower side seal portion 10 is provided between each of them and b. Further, in order to balance the pressure, an upper space portion 11 surrounded by the upper side of the runner 1, the upper seal forming portion 6 of the upper cover, and the upper seal portion 5 of the runner.
And an outer balance which communicates between the lower side (side portion side) of the runner 1, the lower side space portion 12 surrounded by the lower seal constituent portion 8 of the lower cover and the lower seal portion 7 of the runner. A pipe 13 is provided, and similarly, a space 14 on the upper center side surrounded by the upper seal component 6 of the upper cover, the upper seal component 5 of the upper cover, and the draft stove 4 of the lower runner is surrounded. An inner balance pipe 15 that communicates is provided. The center of the runner and the space 1
4 is also communicated with the air supply / exhaust holes 16 formed in the main shaft 2.

In the pump turbine constructed as described above, when the load is cut off, a downward water thrust is generated as follows.

(A) The runner seal outer back pressure (the pressure in the space 11) and the runner side pressure (the pressure in the space 12) are simultaneously caused by the increase in the water pressure in the upstream pipeline and the increase in the rotation speed of the runner. To rise. At this time, if there is a pressure difference between the two, the pressure difference and the water thrust increase.

(B) The draft water pressure drops due to a water hammer. For this reason, the water pressure in the runner side chambers (spaces 12) that are adjacent to each other across the runner lower side seal portion is reduced by the amount of drop by the water hammer. As a result, the balance in (a) above is lost, and the thrust increases accordingly.

(C) Since the draft water pressure in (b) above is applied to the lower surface of the runner inside the runner seal, the thrust increases accordingly.

(D) The back pressure inside the runner seal increases due to the increase in rotation speed. Therefore, the thrust increases.
Since the rotation speed hardly increased immediately after the load was cut off, the draft water pressure drop in (b) above lowers the runner seal inner back pressure via the inner balance pipe, causing a temporary drop in thrust, but eventually. The rise in back pressure inside the runner seal due to the increase in rotation becomes dominant and thrust increases.

(E) The operating point is the above-mentioned S-shaped characteristic, that is, N ₁ (horizontal axis) vs. Q ₁ (vertical axis) perfect characteristic which appears in the hydraulic turbine operating region on the plane (dQ ₁ / dN ₁ )> 0 In the runner, a backflow occurs in the runner, and the outflow amount decreases at the lower end of the runner, causing not only instability but also suction of water from the draft side, causing severe water pressure pulsation. As a result, the runner side pressure is subject to severe pulsation.

(F) Naturally, the influence of the operation in the S-characteristic of the above (e) also appears in the water pressure on the upper reservoir side pipe line, a severe water pressure pulsation occurs, and the pulsating component is added to the thrust of the above (a).

(G) The draft hydraulic pulsation in (e) above is
It promotes the thrust increase in (c) above.

By the way, by increasing the specific speed of the pump turbine, in particular, the K value shown by the product of (specific speed during turbine operation [m-KW unit basis]) and (square root of maximum effective head [m]) is 2450. (Runner seal diameter / runner inlet diameter) increases with the above, so the above (c), (d), (g)
Thrust increase due to the situation becomes serious.

On the other hand, the relationship between the rotational speed of the runner at the time of load shedding and the water pressure in the pipeline on the upper pond side when time is used as a parameter, and the horizontal axis represents the rotation speed [N ₁ ] and the vertical axis represents the flow rate [N ₁ ]. Q
Fig. 10 shows the locus of the operating point of the pump turbine when [ ₁ ] is taken.
(A) and (b) respectively show. In these figures,
The upper reservoir-side conduit pressure characteristic first and second two peaks (maximum values) H _a, H _b appears. These peaks H _a ,
H _b is the rotational speed N _a, but corresponds to a N _b, these rotational speed N _a, N _b has a longitudinal velocity of the rotational speed of the peak (maximum value) N _p. That is, in the process in which the load is cut off from the rotation speed No in the steady operation and the rotation speed rises, the water pressure on the upper reservoir side pipe reaches the maximum (H _a ), and the rotation speed passes the peak N _p. The water pressure that once dropped during the descending process becomes the maximum (H _b ) again.
In this case, the point having the maximum value H _a corresponds to the point A on the locus of the operating point, and the point having the maximum value H _b corresponds to the point B.

On the other hand, the drop in the S-shaped characteristic occurs at almost the same N ₁ point regardless of the number of units, whether one unit is cut off, two units are cut off, or three units are cut off. However, it has been found that in a high specific speed turbine, if the guide vanes are not properly closed, two units are blocked rather than one, and three units are blocked rather than two, and thrust may increase significantly. In other words, it has been found that the thrust increases at a much higher rate than the rate of increase in the effective head due to the increase in the number of shut-off vehicles.

In Japanese Patent Laid-Open No. 54-40946, the lower pond side or the upper pond side pipeline is branched and the other hydraulic turbines or pump turbines have the highest hydraulic pressure on the upper pond side when the load is cut off. The value can be minimized (design water pressure can be minimized), and the load difference of the multiple pump turbines is cut off one after another so that the peak water pressure on the upper reservoir side pipeline does not exceed that at the time of simultaneous cutoff. A method for closing various guide vanes is disclosed. In this method, in the stage of single unit load shedding, the upper pond side pipe line that appears immediately after the load vanishes immediately after the guide vanes close suddenly appears immediately after the peak water pressure reaches the peak value and the water pressure peaks. The guide vanes are managed so as to be closed so as to approximately match the peak value of water pressure. However, in this publication, the abnormal water thrust (runner pushing force) peculiar to load shedding as described above is applied. No mention is made of the reduction of.

The present invention has been made in view of the circumstances of the prior art as described above, and an object thereof is to accurately prevent an abnormal increase in water thrust at the time of load shedding due to a higher specific speed of a pump turbine. It is to provide a method of operating a high specific speed pump turbine that can achieve the above.

[0036]

In order to achieve the above object, the present invention is directed to a case where the upper pond side pipeline is branched near the pump turbine end, and the upper pond side pipeline beyond the branch point is connected to another pump. It is shared with a water turbine, and the product of (specific speed during operation of the water turbine [m-KW unit basis]) and (square root of maximum effective head [m]) is 245.
In a method of operating a high specific speed pump turbine having 0 or more guide vanes, at the time of full load cutoff, before the time when the rotation speed N of the runner reaches the first peak value N _p appeared peak H _a is, as the second peak H _b of the upstream side conduit water pressure immediately after the rotational speed of the runner exceeds the first peak value N _p appears immediately after blocking the guide vanes of the pump turbine is fast closed After that, after the rotation speed of the runner reaches the first peak N _p at the latest, the valve is closed at a speed lower than the speed immediately after the shutoff, and the first peak H _a is the second peak. Is almost equal to H _b , or
The guide vanes are closed so that the peak H _a of the above is larger than the second peak H _b . In this case, when the water pressure pulsation wave is on the peak value, the center of the pulsation wave is set as the peak value.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. Since the system of the pump turbine and the power plant is the same as the above-mentioned conventional example, in the following description, the same reference numerals are given to the same parts as those in the above-mentioned conventional example, and the duplicated description will be omitted. .

FIG. 1 is a diagram showing the state of changes in the water pressure on the upper reservoir side pipeline with the time when the load is cut off as a parameter according to the embodiment of the present invention, and FIG. 2 is the guide vane opening and the pump when the load is cut off. The figure which shows the operating point locus of a water turbine, FIG. 3 is the figure which compared the rotation speed of the runner by the driving method of a pump water turbine, and the water pressure on the upper pond side pipeline, FIG. 4 is a figure which shows the other control example of a guide blade. .

In the method of operating the pump turbine according to this embodiment, when the load is cut off, as shown in FIGS. 1 and 3 (a), the rotational speed of the runner 1 reaches the initial maximum rotational speed N _p . and first appears maximum value (first peak value) H _a of the upper reservoir-side conduit water pressure before, after becoming a speed maximum N _p of the runner 1, the next occurrence in the course of the rotational speed goes down The opening of the guide vane is controlled so that the maximum value (second peak value) H _{b has} a relationship of H _a ≈H _b or H _a > H _b .

In order to control in this way, as shown in FIG. 2, when the load is cut off from the steady operation Dconst, first, the rotation speed of the runner 1 due to the load cut increases to reach the peak N _p . First, the guide vane opening is closed as much as possible to minimize the rotation speed increase range itself, and then to minimize the irregular pulsation due to the S-shaped characteristic.

That is, the S-characteristic becomes smaller as the guide vane opening becomes smaller as described above, and its influence also becomes smaller, so that the operating point of the pump turbine is S after the load is cut off.
Before rushing into the S-characteristics, the incoming S-characteristics are minimized. As a countermeasure against this, again, the guide vanes must be sufficiently closed before the operating point of the pump turbine reaches the S-shaped characteristic. Specifically, the guide vanes are closed like the characteristic of C ₂ as compared with the characteristic of C ₁ of FIG. 2 so that the locus of the operating point is brought closer to the origin as much as possible. For that purpose, the guide vanes are rapidly closed from the steady operation point Dconst to D _1, and after the number of revolutions of the runner reaches the first peak N _p , the speed becomes D ₁ → D ₂ lower than the Dconst → D _1. To close the guide vanes. At that time, Dconst → D ₁ → D ₂
It is more preferable to control as Dconst → D ₃ → D ₄ than to control.

The description of the operating point at that time is as shown in FIG. 2 (b). That is, in the characteristic of C ₁ , the steady operating point Dco
The driving locus follows from nst to Dconst → D ₁ → D ₂ .
In the characteristic of C ₂ , from the steady operating point Dconst to Dconst → D
_The driving locus will be ₃ → D ₄ . By doing so, it becomes possible to operate with the characteristic as shown in FIG. 3A instead of the characteristic as shown in FIG. This is because the first peak value H _a of the upper reservoir side water pressure can be controlled by controlling the guide blade opening, but the second peak value H _b cannot be controlled by the guide blade opening itself. Thus, it is possible to suppress the pressure fluctuation of the pump turbine when the load is cut off within a controllable range.

Note that FIG. 2A shows an example in which only the opening for switching the closing speed of the guide vanes, that is, the hip fold opening is adjusted, but the hip fold opening is not changed as indicated by the dotted line in FIG. By changing the closing speed, as a result, as shown in FIG. 3A, H _a > H _b
You may control so that it becomes. In this way, it is possible to significantly suppress an increase in thrust due to an increase in the number of units that are simultaneously shut off.

[0044]

As is apparent from the above description, according to the present invention, it is possible to reliably suppress an abnormal increase in water thrust at the time of simultaneous shutoff of a plurality of units, which is peculiar to a high specific speed turbine. This facilitates the design of thrust bearings, which are becoming increasingly burdened with higher specific speeds, i.e., higher rotational speeds, avoiding the operational problems of load shedding, and increasing the speed of pump turbines. It is possible to further increase the capacity and capacity.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a waveform of a water pressure in the upper pond side pipeline when the load of the high specific speed pump turbine according to the embodiment of the present invention is cut off.

FIG. 2 is a diagram showing a relationship between an opening of a guide blade and an operating point locus of the high specific speed pump turbine according to the embodiment of the present invention.

FIG. 3 is a diagram comparing the rotational speed of the runner and the water pressure on the upper reservoir side pipe according to the operating method of the pump turbine.

FIG. 4 is a diagram showing another example of control of guide vanes.

FIG. 5 is a diagram showing a schematic configuration of a pumped storage power plant having a plurality of pump turbines that share the upper pond side pipeline, which is the subject of the present invention.

FIG. 6 is a characteristic diagram for explaining an S-shaped characteristic of a pump turbine.

FIG. 7 is a diagram comparing and comparing differences in runner shapes due to differences in specific speed.

FIG. 8 is a diagram showing a relationship between an increase in runner seal diameter and an increase in water thrust due to a higher specific speed.

FIG. 9 is a schematic view showing a structure around a runner of a pump turbine.

FIG. 10 is a diagram for explaining an operating point locus of the pump turbine at the time of load shedding.

[Explanation of symbols]

 1 Runner 2 Spindle 3 Casing 3a Upper cover 3b Lower cover 4 Draft tube 5 Runner upper seal part 6 Upper cover upper seal component 7 Lower runner seal part 8 Lower cover lower seal component 9 Runner outer peripheral seal (upper) 10 runner outer peripheral seal (bottom) 11, 12 space part 101 upper pond 102 upper pond side pipeline (common part) 103 upper pond side branch line 104, 105, 106 upper pond side branch line 107, 108, 109 pump Turbine 100 Shimoike 111,112,113 Shimoike side pipeline

Claims (2)

[Claims] 1. The upper pond side pipeline is branched near the end of the pump turbine, and the upper pond side pipeline beyond the branch point is shared with other pump turbines (specific speed [m- The product of (KW-based unit]) and (square root of maximum effective head [m]) is 245.
In the operating method of a high specific speed pump turbine with 0 or more guide vanes, at full load cutoff, the first (first) maximum value of the upstream side pipe water pressure is reached before the rotational speed of the runner reaches the first maximum value. Appears,
A second maximum value of the upstream pipe water pressure appears in the process of the rotation speed of the runner decreasing from the first maximum value, and the first maximum value is substantially equal to the second maximum value or the first maximum value. So that the maximum value of is larger than the second maximum value, the guide vanes that guide the water to the runner are at a high speed immediately after the load is cut off, and after that, after the time when the rotation speed of the runner reaches the first maximum value. Then, the method for operating a high specific speed pump turbine, wherein the guide vanes are closed at a speed slower than immediately after the load is cut off. 2. When the hydraulic pulsation wave is superposed on the first and / or the second maximum values, the centers of the pulsation waves are regarded as the maximum values, respectively. How to operate a high specific speed pump turbine.