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Publication numberUS3886373 A
Publication typeGrant
Publication dateMay 27, 1975
Filing dateSep 4, 1973
Priority dateSep 4, 1972
Also published asCA985130A1
Publication numberUS 3886373 A, US 3886373A, US-A-3886373, US3886373 A, US3886373A
InventorsMasayasu Okada
Original AssigneeHitachi Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Hydraulic machine control apparatus
US 3886373 A
Abstract
The hydraulic control apparatus is used in an electric power station provided with at least two hydraulic machines, each of which has common use of a surge tank and a penstock extending from an upper reservoir downwardly to where it is connected with the machines by means of branched penstocks at the lower reaches with respect to the surge tank, and comprises means for detecting transitional operation of one of the hydraulic machines as an electric signal, means responsive to the electric signal for rotating cam means, and means responsive to the movement of the cam means for controlling the degree of opening of the guide vanes of the hydraulic machines so as not to exceed the ideal maximum degree of opening of the guide vanes of the hydraulic machines for the particular effective pressure head applied directly to the hydraulic machines.
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United States Patent [1 1 Okada 1 1 HYDRAULIC MACHINE CONTROL APPARATUS [75] Inventor: Masayasu Okada, Hitachi, Japan [73] Assignee: Hitachi, Ltd., Tokyo, Japan [22] Filed: Sept. 4, 1973 211 App1.No.:393,916

[30] Foreign Application Priority Data Sept. 4, 1972 Japan 47-87972 Nov. 29, 1972 .Iapan..... 47-118981 Jan. 29, 1973 Japan 48-11069 Feb. 12, 1973 Japan 48-16633 Mar. 9, 1973 Japan 48-27002 [52] 11.8. C1. 290/52; 290/1; 415/1; 415/26 [51] Int. Cl. F0lb 25/00 [58] Field of Search 290/1, 2, 52; 415/126; 417/279 [56] References Cited UNITED STATES PATENTS 3,163,118 12/1964 Baumann 290/52 3,184,218 5/1965 Hochwalt et al 290/52 3,372,645 3/1968 Willi 290/52 X May 27, 1975 Primary Examiner-G. R. Simmons Attorney, Agent, or Firm-Thomas E. Beall, Jr.

[57] ABSTRACT The hydraulic control apparatus is used in an electric power station provided with at least two hydraulic machines, each of which has common use of a surge tank and a penstock extending from an upper reservoir downwardly to where it is connected with the machines by means of branched penstocks at the lower reaches with respect to the surge tank, and comprises means for detecting transitional operation of one of the hydraulic machines as an electric signal, means responsive to the electric signal for rotating cam means, and means responsive to the movement of the cam means for controlling the degree of opening of the guide vanes of the hydraulic machines so as not to exceed the ideal maximum degree of opening of the guide vanes of the hydraulic machines for the particular effective pressure head applied directly to the hydraulic machines.

11 Claims, 15 Drawing Figures lITECTlNG MEANS Pmmmmv 1915 3.8863 73 FIG.

PAIENIEH TAT 27 1915 POWER SYSTEM TRANSMISSION SYSTEM FIG. 4

MEANS FOR DETECTING TRANSMISSION ON OFF MEANS FOR DETECTING POWER RATIO CHANGE OF ELECTRIC CURRE MEANS FOR DETECTING ACCELERATION sum 3 FIG. 6

LLfIZAMPLIFIER DETECTING MEAQ PATEbHEW-ti 27 1915 FIG. 9b

SHEET J? GUiD'E "JANE OPENING MEANS AUXILIARY m i n2 0/ J 13 TRANSITIONAL NORMAL & OPERATION OPERATION TRANSIT'ONAL OPERATION @av TRANSITQMAL NQRMAL TRANSITIONAL OPERAUQN TOPERATION OPERATION mnzmsuwzv ms 3886373 SHEET 5 FIG. I00

TiME 1 HYDRAULIC MACHINE CONTROL APPARATUS BACKGROUND OF THE INVENTION The present invention relates to the type of control apparatus for hydraulic machines such as water turbines, pumps, or reversible pump-turbines wherein the hydraulic machines are each connected with their respective penstocks that are branched from a common penstock with a common surge tank, which is connected with an upper reservoir.

In a hydraulic machine such as a reversible pumpturbine used in a pumped storage power station, its capacity is increasing in recent years so that at the present time it is quite large. In such a station, a flume system is used wherein a surge tank and a penstock are connected to an upper reservoir, with a plurality of pumpturbines being fed therefrom, rather than a system wherein each pumpturbine has its own penstock and surge tank leading to the reservoir; the system of a common penstock and surge tank is used because it is more economical with respect to the construction and maintenance of the flume system. The section area of the penstock in the flume system and the size of the surge tank have in recent years become very small, because it is difficult to make the area larger due to the structural strength problem occurring through the adoption of high head regions for purposes of economy of the construction of the flume system, and because of the decrease in cost for construction of smaller flume systems.

In the abvementioned prior art type of electric power station, a transitional operation such as stopping, starting, rapid variation of load, or an interruption of load occurs in one or more of the plurality of hydraulic turbines or the like which make use of the common flume system, there will occur variations in the amount of the water or the like motive fluid flowing in the hy draulic turbine with time induced disturbances in the flume system, such as a water hammer phenomena or fluctuations of the water level in the surge tank. Therefore, the disturbances have an influence on the other hydraulic machines. This influence appears to be a fluctuation of the effective pressure head of the other hydraulic machines or machine.

On the other hand, information regarding a pressure head in order to control an output, a quantity of water pumped, and an rpm. of the hydraulic machine is due to a static head or difference in water level between the upper reservoir and the lower reservoir. As the fluctuation of the effective head due to the disturbances above mentioned in the flume system is not included in the information regarding the total static head, control of the hydraulic machine according to fluctuations of the effective head is not accomplished. In such a case, the hydraulic machine goes into an overload operation. Therefore, the strength of the machine becomes insuf ficient and vibration of the machine increases rapidly. In the prior art as the result of the above-mentioned problems, there have been several types of control, one of which in the case of load interruption, rapidly closes the guide vanes of a turbine by a predetermined safety opening degree with an information given by detecting the load interruption from transient voltage rise of a generator directly connected to the turbine, and another of which switches over a control apparatus from one turbine having a potentiometer for normal operation to another control apparatus having a potentiometer for safety operation by the information of the voltage rise.

However, the control apparatus which controls other turbines by the information of the voltage rise occurring at the time when the load of the turbine is interrupted has the following defects. Namely, the voltage rise is brought about in case of the load interruption. but it is not brought about in the case of an input interruption of pumping operation, or even though it is brought about, the amount of the voltage rise is very small, so that it is not a proper signal for use in detecting disturbances in the flume system due to the input interruption. Where an automatic voltage regulator works sufficiently in case of relatively slow load variation, a rapid load increase or a stopping operation or a starting operation will have a result that the voltage rise is not brought about. Therefore, it is impossible to detect the disturbances in the flume system by the voltage rise.

Further by providing, for example, a protecting sys tem for safety operation besides the automatic voltage regulator, it makes the control system including both of them, so complicated to switch over to operation due to the protecting apparatus from the operation due to the automatic voltage regulators that disadvantages wherein it lowers its reliability and economic strength are brought about. Further. it is technically difficult to make such a control apparatus for the safety operation against all the flume system disturbances occurring as the result of, for example, starting, stopping, sudden change of load, interruption of input, or interruption of load, and the considerable disadvantages of providing a plurality of control apparatus for safety operation for exclusive use are brought about.

SUMMARY OF THE INVENTION It is an object of the present invention to provide hydraulic machine control apparatus which is simple in construction and reliable in operation for control and response to disturbances in the flume system without the need ofa large flume system, so that an economical electric power station with satisfactory control may be constructed.

The hydraulic machine control apparatus according to the present invention is used in an electric power sta tion provided with at least two hydraulic machines, each of which has common use of a single surge tank and penstock leading from an upper reservoir, by being connected thereto with each of a corresponding plurality of penstocks branching from the main penstock on the lower reaches of the main penstock with respect to the surge tank. It is characteristic of the present invention that the hydraulic machine control apparatus comprises means for detecting transitional operation of an hydraulic machine as electric signals, in combination with means responsive to the electric signals for rotating cam means, and means responsive to the movement of the cam means. The cam means are so constructed that even though sudden changes of a pressure head that is actually applied to the hydraulic machine will produce a degree of opening of the guide vanes of the hydraulic machine that does not go beyond an ideal maximum degree of opening of the guide vanes for the effective pressure head.

BRIEF DESCRIPTION OF THE DRAWING Further objects, features and advantages of the present invention will become more clear from the follow ing detailed description of a preferred embodiment of the present invention as shown in the accompanying drawing, wherein:

FlG. l is a schematic representation of an electrical power station employing the present invention;

FIGS. 2 5. there are schematically shown hydraulic machines provided with means for detecting a transi tional operation for usage in the present invention:

FIG. 6 is a schematic view of an embodiment of an hydraulic machine control apparatus according to the present invention, shown in detail;

FIGS. 70 7c each show perspective views of cams used in the embodiment of the hydraulic machine con trol apparatus of FIG. 6;

FIG. 8 is a schematic diagram of an electric circuit for controlling a solenoid valve used in FIG. 6',

FIGS. 9a and 9!) each show graphs showing charac teristic curves of guide vanes operating an hydraulic machine with effective head as an abscissa and the dc gree of guide vane opening as the ordinate;

FIG. [a is a graph showing the characteristics of an hydraulic machine according to the prior art hydraulic machine control apparatus; and

FIGS. 10b and 100 each are graphs showing characteristics of an hydraulic machine having the control apparatus of the present invention,

DETAILED DESCRIPTION OF THE INVENTION Before a preferred embodiment of the present invention is described in detail. the fluctuations of the effec tive pressure head applied to the hydraulic machine, for example, a reversible pump-turbine, due to a transitional operation such as stopping of another pumpturbine, will be described referring to FIG. 1. While as mentioned above, various hydraulic machines may be employed with the present invention to be controlled thereby, the description will refer to a reversible pumpturbine using water as the motive fluid for purposes of the description of a preferred embodiment.

In FIG. I, reversible pump'turbines SA and 5B with generator-motors 6A and 6B are connected with branched penstocks 4A, 4B, respectively, which penstocks 4A. 4B are branched from a common penstock 2 that leads to an upper reservoir 1. While the drawing is not to scale, it is understood that the branch penstocks 4A, 4B extend from the lower reaches of the common main penstock 2 that extends substantially the entire vertical distance from the reservoir to the hydraulic machines. On the lower reaches of the penstock 2, there is a surge tank 3. Draft tubes 7A, 7B are branched from a main draft tube 8 from a lower reservoir 9. In such an electric power station, the pump turbines 5A, 58 have common use of the surge tank 3, the penstock 2 and the draft tube 8. All of the above structure may be of conventional construction and therefore will not be described in greater detail. While more than two pumpturbines may be provided, two will suffice for purposes of illustration.

1n the case where stopping of the pump-turbine 5A is instructed during pump operation of the pump turbines 5A, 58, input of the generator-motor 6A is interrupted and the water pressure in the branched penstock 48 drops for an instant, and the pressure in the branched draft tube 75 rises for an instant. After such a pressure drop in the branched penstock 4B and a rise in pressure in the draft tube 73 are repeated many times. fluctuation of the pressure decreases gradually and then disappears. On the other hand, when the pump operation of the pump turbine 5A is stopped, a level ofwater in the surge tank drops for an instant. and then reaches a steady state to maintain a certain level. which level may gradually rise according to a rise of water level in the upper reservoir 1. In such a case, substantial pressure head applied to the pump-turbine 5B is not one due to the difference of water levels between the upper reservoir 1 and the lower reservoir 9, but one after reduction ofthe pressure drop in the pcnstock 4B and the pressure rise in the branched draft tube 78 from the pressure head due to the difference of the water level between the upper and lower reservoirs l and 9, respectively. On the other hand, in the case where an instruction is given to stop the pump-turbine 5A, during operation of both pump-turbines, the pump turbine 58 receives higher pressure head than it receives when both of the pump-turbines are in operation. Thus, the effective pressure head applied directly to one of the pump turbines may vary greatly from the static pressure head between the reservoirs,

Thus it is seen that when any one of a plurality of the hydraulic machines SA, 58 which have a common usage of the surge tank 3 and the penstock 2 has a transitional operation, the others ofthe hydraulic machines will have an effective pressure fluctuation due to such transitional operation. Accordingly, the pump-turbine should have its control based on the effective pressure head applied directly to it, as recognized by the present invention.

FIG. 9a is a graph showing an ideal characteristic curve of the degree of guide vane opening with effective head as an abscissa and degree of guide vane opening as an ordinate. A portion 11] of the characteristic curve 110 shows in full lines an ideal maximum degree of guide vane opening in the region of an effective pressure head during normal operation of the hydraulic machine, and each of the portions 112 and 113 show the ideal maximum degrees of guide vane opening in the region of an effective pressure head during a transitional operation of the hydraulic machine, respectivelyv If any one of a plurality of hydraulic machines which have a common use ofa surge tank and penstock, such as the pump-turbine SA, undergoes a transitional operation, the others of the hydraulic machines, that is the pump-turbine 58, will have an effective pressure fluc tuation, such as a pressure rise 114 or a pressure drop 115 as shown in FIG. 9b, In the case of the pressure rise 114, the degree of guide vane opening of the pumpturbine 43 should be increased along the characteristic curve 110 by the point at which the characteristic curve 110 and an arrow 12] intersect. When the fluctuation 121 or 122 of pressure head due to a transitional operation takes place, if the degree of guide vane opening is controlled along such a characteristic curve that a degree of guide vane opening does not exceed the maximum degree of guide vane opening even though such a pressure rise takes place, the present in vention will be achieved,

Embodiments of hydraulic machine control apparatus according to the present invention will be described hereinafter referring to FIG. 1 and FIG. 6 through FIGS, 9a and 9b.

In PK]. 6, detecting means 101, such as the water level meter 103, 13 of FIG, 1 detects the water level or pressure head of the reservoirs as an electric signal.

The detected electric signal is transmitted to a motor 98 through an amplifier I00 and electrical leads 99. The motor 98 rotates a worm gear 97 according to the electric signal from the detecting means 101. The worm gear 97 rotates the cams 79, 80 that are rotationally fixed to a shaft 74 that is supported at its opposite ends in bearings 75, 76 to be driven through gear 77 fixed to the shaft 74 and being in meshing engagement with the worm gear 97. The cam 79, which is constructed as shown in FIG. 7b, will control the guide vane opening degree along the characteristic curve 111 of FIG. 9a, and has a shape so that a distance R be tween the outer surface of the cam 79 and the center of the cam 79 increases gradually as the measuring point thereof advances clockwise, which will produce a corresponding movement of the follower lever 71, one end of which is pivotally connected to a stationary fulcrum 73. The follower lever 70, with its stationary fulcrum 72 is correspondingly in engagement with the outer cam surface of the cam 80. The levers 70 and 71 are kept in engagement with their cams 80, 79 by cam change over means comprising cylinders 85, 86, pistons 83, 84 slidably received within the cylinders, compression springs 87, 88 for upwardly biasing the pistons 83, 84, stoppers 89, 90 disposed within the cylinders 85, 86, oil pipes 91, 92 attached to the upper portions of the cylinders 95, 96, and a change over valve 93 or a solenoid valve with an electromagnetic valve 94 which switches over the oil passages 91 and 92 to pass oil to an oil reservoir 96 or from a source of pressurized oil in passage 95. In the position of FIG. 6, the cam 80 is not in contact with the lever 70, one end of which is pivoted at the fulcrum 72. The movement of the cam 79 is transmitted to a pinion gear 56 through the power train involving the cable 69, a pulley 67 fixed to a shaft 73 that is rotatably supported in bearings 64, 65, a pulley 62 fixed to the shaft 63, a cable 60 passing over an idler change direction pulley 61, a pulley 58, and the shaft 57 that carries the pulley 58 and gear 56. The weight 59 will provide the necessary bias for the pulleycable system. Thus it is seen that vertical movement of the lever 71 as controlled by the cam 79, is changed to a rotational movement of the pinion gear 56 through the connection of the above-mentioned power train. The rotational movement of the pinion 56 is changed to a vertical movement of the rack 55 that is in meshing engagement with the pinion 56 for reciprocation of the rod 54 extending downwardly from the rack 55 for correspondingly reciprocating the pistons 53 and 52 that are slidably inserted in a cylinder 49, which cylinder 49 is in turn reciprocated within a guide sleeve 50. The lower end of the cylinder 49 is connected to one end of a lever 46 by means of a pivot link connection 48, and the lever 46 is pivoted on the stationary fulcrum 47 at its intermediate portion. The other end of the lever 46 is connected to one end of the piston rod 45 of the auxiliary valve comprising a piston 41 slidably received within a cylinder 42.

In operation, if the rack 55 moves downwardly, pressurized oil is supplied to the lower chamber of the cyl inder 42 through oil passage 51, the cylinder 49, and an interconnecting oil passage 44; thereby, the piston 41 is moved upwards at the same time the cylinder 49 is moved downwards through the interconnection of the lever system 48, 46 and the rod 45, so that oil supplied to the auxiliary valve is interrupted to reach a steady state for the top end of the lever at a new predetermined position. The movement of the lever 40 as determined by the piston 41 is transmitted by a lever 33 to a rod 30 of a distributing valve that comprises pistons 28, 29 and a cylinder 27; the lever 33 is pivoted at its opposite ends as shown to the piston rods 30 and 40, respectively, and at an intermediate portion thereof it is pivotally connected to a lever 35. If the rod 40 moves upwards, the rod 30 will correspondingly move downwards, because of the connecting lever 33 and the lever 35 that acts as a fulcrum for the lever 33. When the pistons 28, 29 move downwards with the rod 30, pressurized oil is admitted to a servomotor comprising a cylinder 20 and a piston 21, through an oil passage 31, the cylinder 27, and an oil passage 26 to move the piston 21 toward the right as shown in FIG. 6, which piston 21 is connected to a rod 22 having a cam wedge 23 fixed thereon and further to which a guide vane 24 is connected. The rightward movement of the piston 21 moves the lever 35 upwards against the bias of a compression spring 39 disposed between a flange 37 provided on the lever 35 and a stationary base 38, due to the interengagement of the cam 23 and the follower 36, which follower is carried by the lever 35. Thereby, the supply of the pressurized oil to the distributing valve is interrupted due to the lifting of the fulcrum point for the lever 33 and the corresponding raising of the piston rod 30 to stop the piston 21 at the proper position, namely, to provide a new position for the guide vane 24 at the proper degree of opening.

The operation will be described wherein one of the hydraulic machines, for example the pump-turbine 4A, undergoes a transitional operation while the other hydraulic machines such as the pump-turbine 4B, maintain normal operation. With such transitional operation, the solenoid valve 93 will operate to thereby remove the lever 71 from contacting engagement with the cam 79 and to establish contacting relation between the lever and the cam 80. The cam 80 is configured as shown in FIG. 76, so that the degree of opening of the guide vanes 24 in relation to the effective pressure head changes along the characteristic curve of FIG. 9b; this is accomplished by releasing the pressurized fluid from above the piston 84 to allow the connecting rod 82 to move upwardly under influence of the compression spring 88 and to provide pressur ized biasing fluid above the piston 83 to overcome the spring bias 87 to move the connecting rod 81 downwardly under bias. With reference to the cam 80, the distance R between an outer surface thereof and the center thereof decreases gradually at first'and then later increases gradually, as the measuring point of the distance R advances or rotates clockwise from the left hand end of a normal operating region as illustrated in FIG. 70. In short, during transitional operation of the pump-turbine 4A, the guide vanes 24 of the pumpturbine 48 are controlled by means of the cam 80 and not the cam 79, which cam 79 was in control during normal operation. After a lapse of a predetermined time, the control apparatus is restored to the original normal control cam 79.

As electrical control circuit for the solenoid valve 93 is illustrated in FIG. 8, wherein a coil S of the solenoid valve 93, a time relay and an auxiliary relay each are connected in parallel to the lines L and L Switches A3 and A2 each are added to the coil S and the time relay, respectively, in series. Switches SW and b are added to the auxiliary relay in series. A switch a, is con' nected in parallel with the switch SW. The switch SW is operated through a detecting means 102, which detects a transitional operation as an electric signal. When the detecting means detects the transitional operation of the pump-turbine 4A, the switch SW makes contact, the auxiliary relay operates, the switches a a are operated by the auxiliary relay to make contact. Thereby, the solenoid valve 93 operates and changes cam operation from the cam 79 to the cam 80 for the predetermined time as determined by the time relay. The time relay will thereafter break contact of the switch b after the lapse of the predetermined time to restore the electrical control circuit of the solenoid valve 93 to the original condition wherein the cam 79 will be in operation.

The detecting means 102 may be, as shown in FIG. 2, a pressure relay I4 responsive to more than a predetermined amount of fluctuation of pressure head between the input to the casing of the pump-turbine and the draft tube adjacent to the pumpturbine 5B; or it may be means of FIG. 3 for detecting acceleration of the motor-generator 6A connected to the pumpturbine 5A; or it may be means 16 for detecting the on off of switch means provided between the generatormotor 6A and connected to the pump-turbine 5A and a power transmission system 17 as shown in FIG. 4; or such may be the means 18 for detecting the ratio of the change of an electric current of an electric system added in parallel to the generator-motor 6A for example a highpass filter, as shown in FIG. 5. Any one of these connecting means may be attached to a pumpturbine and motor-generator unit for detecting disturb ances for operation of the circuit shown in FIG. 8 for controlling the cam switchover of FIG. 6 to obtain the operating characteristics of FIG. 9b, as explained above.

The present invention may further be accomplished with a control apparatus having the cam 78 of FIG. 7a, which cam 78 is made so that the degree of opening of the guide vanes 24 with respect to the effective pressure head changes along the ideal characteristic curve 110 of FIG. 90 having the characteristic curve portions 111, 112 and 113 used instead of the cam 79, with contact between the lever 70 and the cam 80 being released. A water level meter 10 detecting the level of the water of the surge tank 3 as electric signals or water pressure gauges Ill and 112 which detect the pressure heads in the casing of the pump-turbine 5B and in the draft tube adjacent to the pump-turbine 53 may be used. The hydraulic machine control apparatus in FIG. 6 is able to control the degree of opening of the guide vanes 24 approximately along the ideal characteristic curve 110 with the above apparatus since each of the water level meter 10 and the water gages 111, 112" is able to detect transitional phenomena, the cam 78- has a region thereof such that the guide vanes 24 is controlled according to the transitional operation, and the cam 78 is made so that the distance R between an outer surface and the center of the cam 78 decreases in the left transitional operation region as shown in FIG. 7a from the left side thereof toward the right side, and increases in the normal operating region and in the right transitional region from the left side toward the right side. Thus, only the single cam 78 would be employed and the region of the cam controlling operation would be determined by the water level and pressure sensing means mentioned above as a further embodiment of the present invention.

In FIG. 100, there is shown the characteristics of a pumpturbine, with a lapse of time as an abscissa according to a prior art control apparatus. The graph is an ideal characteristic curve of the degree of opening of the guide vanes to be controlled in a transitional operation. The graph 13101 is a characteristic curve of the degree of opening of the guide vanes according to a control system of the prior art. As fluctuations of a pressure head during the transitional operation are not detected, the opening degree of the guide vanes during normal operation is maintained also during the transitional operation. The curve [320 shows a load change ofa pumpturbine in case the hydraulic machine is controlled by a control system of the prior art. The graph 134 shows the allowable maximum load. An area 133 shown by cross hatching shows that the load of the hydraulic machine is beyond the allowable maximum load at intervals during the transition period. In such a case, intensity of vibration is quite large as shown by the vibration graph 1350.

With the present invention, with the cam 78 used therein, a characteristic curve l31b of degree of opening of the guide vanes 24 is controlled approximately along the ideal maximum degree of guide vane opening 130 as shown in FIG. 10b, because an effective pressure head which changes with time is detected, and the degree of opening of the guide vanes is controlled thereby. Accordingly, fluctuations of the load I32b are not beyond the allowable maximum load level I34, and the intensity of the vibration as shown by the graph 13512 is less.

In the case of the embodiment of the present inven tion wherein the cams 79 and 78 are used, the characteristic curve of the degree of opening of the guide vanes 24 is shown by the graph 1316 such that the degree of opening of the guide vanes 24 is closed by a predetermined safety degree of opening as compared with the ideal curve 130. Accordingly, the load charige to the degree of guide vane opening is shown by the curve 1320, which is not beyond the allowable maximum load curve 134, and the intensity of the vibrations is less than the previous plots.

The embodiments are mainly described with respect to the transitional operation due to stopping of the pumping operation, however the present invention is able to be applied to all disturbances in the pressure within the flume system.

While various embodiments, variations and modifications have been described in detail with respect to the present invention, further embodiments, modifications and variations are contemplated within the spirit and scope of the present invention as defined by the following claims.

What is claimed is:

l. Control apparatus for hydraulic machines that are arranged so as to receive hydraulic fluid commonly from a single penstock connected at its upper portion to an upper reservoir and connected at the lower regions of the system to a plurality of hydraulic machines by branch penstocks with the provision of a single surge tank common to the hydraulic machines, which hydraulic machines have movable guide vanes for controlling the flow of hydraulic fluid through the machines, respectively, comprising: monitoring means for producing an electric signal in response to transitional operation of at least one of the hydraulic machines; movably mounted cam means; operating means responsive to said electric signal for moving said cam means; and adjusting means responsive to the movement of said cam means for controlling the degree of opening of the guide vanes of at least one of the other hydraulic machines.

2. The control apparatus of claim I, wherein said cam means and adjusting means control the degree of opening of the guide vanes of the other hydraulic machine so as not to exceed a predetermined ideal maximum degree of opening as correlated to the effective pressure head across the input and output of the other hydraulic machine.

3. The control apparatus of claim 2, wherein said monitoring means detects the water level change of the surge tank to produce a correlated electric signal.

4. The control apparatus of claim 2, wherein said monitoring means detects the motive fluid pressure difference between the inlet and outlet of the other hydraulic machine to produce a correlated electric signal.

5. The control apparatus of claim 2, wherein said cam means comprises at least two separate cam surfaces, one of which is configured for a normal operation of the other hydraulic machine and the other of which is configured for a transitional operation of the other hydraulic machine, and said operating means further including means for switching control from one cam portion to the other cam portion in response to the electric signal of said monitoring means.

6. The control apparatus of claim 5, wherein said monitoring means includes means for detecting the level of water in the upper reservoir and producing a correlated electric signal for controlling the operating means so as to move the cam means in correlation with the detected water level to correspondingly control the guide vane opening correlation to the detected water level, and said monitoring means further including means for detecting acceleration of the one hydraulic machine rotation to produce a corresponding electric signal; said means to switch being actuated by said acceleration electric signal for determining the cam portion to be moved for controlling the operation of said adjusting means.

7. The control apparatus of claim for use where the one hydraulic machine is in driving relation with a generator and power transmission system connected to the generator by a switching means, wherein said monitoring means includes means for detecting the level of water in the upper reservoir and producing a correlated electric signal for controlling the operating means so as to move the cam means in correlation with the detected water level to correspondingly control the guide vane opening correlation to the detected water level, and further wherein said monitoring means includes means for detecting the on-off of the switching means between the generator of the one hydraulic machine and the power transmission system connected to the generator for producing an electric signal correlated to the on-off switching; and said means to switch being responsive to said on-off switching signal for correspondingly switching the cam portion to be operative for controlling said adjusting means.

8. The control apparatus of claim 5 for use with a system employing a generator driven by the one hydraulic machine and in parallel electric circuit with an electric system, wherein said monitoring means includes means for detecting the level of water in the upper reservoir and producing a correlated electric signal for controlling the operating means so as to move the cam means in correlation with the detected water level to correspondingly control the guide vane opening in correlation to the detected water level, and further wherein said monitoring means includes means for detecting the ratio of the change of an electric current in the electric system in parallel with the generator of the hydraulic machine and producing an electric signal correlated to the ratio; and said means to switch being responsive to said ratio electric signal for switching said cam portions to determine which of said cam portions will be operative for control of said adjusting means.

9. The control apparatus of claim 5, wherein said monitoring means includes means for detecting the level of water in the upper reservoir and producing a correlated electric signal for controlling the operating means so as to move the cam means in correlation with the detected water level to correspondingly control the guide vane opening correlation to the detected water level, and said monitoring means further including means for detecting fluctuations in the pressure applied between the inlet of said other hydraulic machine and the outlet of said other hydraulic machine for producing a corresponding electric signal correlated to such pressure fluctuations; said means to switch being responsive to said electric signal correlated to the pressure fluctuations for switching said cam portions to determine the cam portion that will be operative to control said adjusting means.

10. A control method for hydraulic machines that are arranged so as to receive hydraulic fluid commonly from a single penstock connected at its upper portion to an upper reservoir and connected at the lower regions of the system to a plurality of hydraulic machines by branch penstocks with the provision of a single surge tank common to the hydraulic machines, which hydraulic machines have movable guide vanes for controlling the flow of hydraulic fluid through the machines, respectively, comprising the steps of: monitoring the transitional operation of at least one of the hydraulic machines and producing an electric signal correlated to the transitional operation; moving a cam in responsive to said electric signal and thus in response to the transistional operation; and controlling the degree of opening of the guide vanes of at least one of the other hydraulic machines in response to the position of the cam so as not to exceed a predetermined ideal maximum degree of opening as correlated to the effective pressure head across the input and output of the other hydraulic machine.

11. The control method of claim 10, including providing at least two separate cam surfaces for said cam, one of which is configured for a normal operation of the other hydraulic machine and the other of which is configured for a transitional operation of the other hydraulic machines; and controlling the degree of opening of the guide vanes according to the position of one cam surface during normal operation and according to the position of the other cam surface during transitional operation.

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4097183 *Jul 9, 1976Jun 27, 1978Bechtel International CorporationMethod of and apparatus for controlling by-pass valve
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Classifications
U.S. Classification290/52, 415/26, 290/1.00R, 415/1
International ClassificationF03B15/00, F03B15/06
Cooperative ClassificationY02E10/226, F03B15/06
European ClassificationF03B15/06