ASYNCHRONOUS CONVERSION METHOD AND APPARATUS FOR USE WITH VARIABLE SPEED TURBINE HYDROELECTRIC GENERATION

Abstract: A hydroelectric power generation system (20) generates electrical power for an electrical utilization system (72). A controller (42) obtains a requested output electrical power level from a hydro-turbine unit (70) by using a signal indicative of water head (hmeas) to control speed of an asynchronous rotary converter (50) coupled to the hydro-turbine unit and to control gate position of the hydro-turbine unit. The requested output electrical power level is applied from the hydro-turbine unit via the rotary converter to the electrical utilization system. In one embodiment, the controller (42B) accesses an updatable memory wherein Hydraulic Hill Chart information is stored. In another embodiment, the controller (42C) also includes a real-time automatic governor which uses a signal indicative of ac transmission frequency to the electrical utilization system to control the output electrical power level of the rotary converter.

Description: ASYNCHRONOUS CONVERSION METHOD AND APPARATUS FOR USE WITH VARIABLE SPEED TURBINE HYDROELECTRIC GENERATION BACKGROUND This application is a continuation-in-part of United States Patent Application Serial No. 08/426,201 filed April 21, 1995 by Hark A. Runkle and entitled "INTERCONNECTION SYSTEM FOR ELECTRICAL SYSTEMS HAVING DIFFERING ELECTRICAL CHARACTERISTIC", and is related to simultaneously-filed United States Patent Application Serial No. 03/ , (attorney docket 17-GΞ-554.) entitled "INTERCONNECTION SYSTEM FOR TRANSMITTING POWER BETWEEN ELECTRICAL SYSTEMS", both cf which are incorporated herein by reference. 1. Field of Invention This invention pertains to hydroelectric power generation, and particularly to method and apparatus for improving performance of a hydroelectric power generation system. 2. Related Art and Other Considerations In :he generation of electrical po*- using hydro- turbines, hydro-turbine units are enclosed m a dam, wi t h water (e g, river or lake) flow tnrougn the dam cemg use d to drive (e.g , rotate) the hydro-turbine unit So driven, the hydro-turbine unit has a shaft speed which is proportional to the frequency of the electrical power ou u t produced by the hydro- urbine un t. Typically the hydro- turbine unit is a synchronous machine, meaning that the average speed of normal operation of the hydro-turbine unit is exactly proportional to the frequency of the electrical utilization system to which t is connected. The generation of electrical power using hydro- turbines presents complex technical and environmental issues. For example, if a hydro- urbine unit is operated at a constant speed, several problems may manifest For example, the turbine may cavitate at high and low loads (e.g., high and low water flow rates) . Additionally, pressure variations created by turbine buckets of a hydro- turbme unit may harm fish passing through the turbine Moreover, t hydro- urbine units operated at constant speed have numerous limitations, including restricted ability to affect power system frequency, slow active power adjustment, lower than optimum turbine efficiency, and a restricted active power operating range .which subsequently restricts the power system, water head and flow ranges) 7/16627 Since the hydro- urbir.e uni is a syncnrcr.c s machine, slowing down the shaft speed cf the turb .-.e also reduces the synchronous frequency of th output A reduction in synchronous frequency cf the hydro-t rb : __ ,.-.. - output s unacceptable when the hydro- urbine un t cu directiy coupled to a user power grid. Various efforts have been underway to achieve a variable speed hydro turbine According to one effort, documented by Goto et al. , "Power System Stabilizing Control By Adjustable Speed Pumped Storage Power Station Using Stabilizing Signals", CIGRΞ Symposium Tokyo 1995, the main hydro generator is modified to apply a variable-frequency current to the field winding via a cycloconverter- ype of excitation system. United States Patent 4,743,327 to Shiozaki et al. discloses a variable speed hydro turbine wherein control is accomplished using power and speed measurements of the main hydro generator in a closed loop configuration. Closed loop operation presents e.g., dynamic stability concerns (at least in a short time frame after a request for power change) . What is needed, therefore, is a variable speed hydro turbine system which is efficient and stable. /16627 - _ SUMMARY A hydroelectric power veneration system generates electrical power for an electrical utilization system The hydroelectric power generation system comprises a hydro- turbine unit which is driven to generate hydro-turome output electrical power An asynchronous rotary converter is coupled to receive the hydro-turbine output electrical power and is operated by a controller to yield a requested converter output electrical power level to the electrical utilization system In one emoodiment, the controller uses a signal indicative of water head (h,...) to control a speed of the rotary converter (and consequentially the hydro-turbine unit) and gate position of the hydro-turbine unit for yielding the requested converter output power level to the utilization system. In another embodiment, the controller also includes a reaJL-time automatic governor which uses a signal indicative of ac transmission frequency to the electrical utilization system to control the output electrical power level of the rotary converter. Controlling the speed of the variable speed hydro- turbme unit involves using the signal indicative of water head to access an updatable memory wherein Hydraulic H ll Chart information is stored To this end, in one embodiment a Hill Chart updacer is provided. 16627 BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other oojects, features, and advantages of the invention will be apparent from the following more particular description of preferred emoodiments as illustrated m tne accompanying drawings m whicn reference characters refer to the same parts throughout the various views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Fig. IA is a schematic view of a hydraulic turbme/generator system according to a first embodiment c: the invention. Fig. IB is a schematic view of a hydraulic turbme/generator system according co a second embodiment c the invention. Fig. 1C is a schematic view of a hydraulic turbine/generaror system according to a third embodiment o: the invention. Fig. 2 is a scnemacic view of an asynchronous converter according co an embodiment of the invention. Fig. 3 is a partial schematic, partial perspective view of the asynchronous converter of Fig 2. Fig 4 is a Hill Chart utilized to expia r principles of operation of the hydraulic turbme/ge. ' :ratcr system of the invention. Fig. 5 s a schematic diagram of functions performed by a predictive controller included in a c ' ^ ntrcl system of the hydraulic turbme/generator system of the invention. Fig. SA and Fig. 53 are graphs reflecting tables stored the predictive controller which are used for generating output signal ω. and a gate position or gate order command. DETAILED DESCRIPTION OF _____ DRAWINGS Fig. IA shows a hydraulic turbine/generator system 20 according to a first embodiment of the invention. System 20 is situated at a dam 22 which dams up water of a body of head water 24.. Head water transducers 25 are mounted on or proximate dam 22 for ascertaining a height "h" of head water 24. In conventional manner, dam 22 has a penstock 25 through which water (from the body of head water 24) is channeled to turbine chamber 28. Draught tube 30 connects an outlet of turbine chamber 28 to a body of tail water 32. System ;_ includes turbine 40, control system 42 A , hydraulic generator - . and, asynchronous converter 50. Turbine 40 is situated turo e chamber 23 m conventional fasnicn. and has an output shaft 60 which provides mechanical power flow to generator 44 Turbine 40 has a wicket gate controller 41 which controls positioning cf an unillustrated wicket gate mechanism included in turbine 40 Generator power supply 62 (also known as a generator field exciter) supplies field current on lines 64 to hydraulic generator 44. In conventional manner, generator power supply 62 receives its power input on lines 56 and an exciter input signal on line 67. As termed herein, turbine 40 and hydraulic generator 44 comprise a hydro-turbine unit 70. Moreover, in view of its operation as explained hereinafter, asynchronous converter 50 is also known as an interface for coupling hydro-turbine unit 70 to an AC Power System such as utility or utilization system 72. In utilization system 72, electrical power may vary and is in a predetermined utilization electrical frequency range. A utility requirements signal (carried on 73 from a control panel 74) is indicative of a power level P- currently required by utilization system 72. 16627 -a- As shown in Fig. IA, control system 42. includes predictive controller 76. The power order or power level signal P, from control panel 74 13 applied as a first i-put to predictive controller 75. A second input signal to predictive controller 76 is the signal h,.., applied from water head transducer 25. A first output of predictive controller 76 is a gate position command which 13 applied cn line 90 to wicket gace controller 41. A second output signal ω 30 of predictive controller 76, indicative of the desired rotational velocity of hydro-turbine unit 70 (_ 0 being the actual rotational velocity of hydro-turbine unit 70) , is applied to asynchronous converter 50 in the manner more particularly indicated hereinafter. Fig. 4 shows a conventional "Hill Chart" of a type well known in the prior art and which is useful for an understanding of the funccion of the predictive controllers shown herein. The independent (horizontal) axis of the Hill Chart is proportional to the speed ω,.„ of hydraulic generator 44 and inversely proportional to the square root of the water head "h" (as determined by water head transducer 25) . The dependent (vertical) axis is power cut of the generator. Each trace on the plot of the Hill Chart of Fig. 4 represents a different position of the wicket gate as governed by wicket gate controller 41. For each gate position and water head measurement, there is an optimum value of speed to maximize power. /16627 Fig. 5 illustrates functions performed by predictive controller 75. As indicated previously, predictive controller 6 receives the head water measurement signal h_.„ from water head transducer 25 and the ordered power signal P 0 (e.g., from panel " ) . Using these two input signals, predictive controller 75 consults a first look-up table 94 to obtain a value "gate order" for use as the gate position command to apply on line 90 to wicket gate controller 41, and consults a second look-up cable 95 to obtain the desired rotational velocity signal _._. for application on line 92 and for use in driving asynchronous converter 50. It will be understood by the man skilled in the art that, in one embodiment, predictive controller 76 comprises a processor with look-up tables 94 and 95 being stored in memories such as one or more read only memories (ROMs) . The gate position command is applied on line 90 to gate wicket controller 41. The man skilled in the art understands how wicket gate controller 41 functions to concrol positioning of the wicket gate mechanism included turbine 40. 16627 -10- The output signal ω. 0 applied on line 92 from predictive controller 76 to asynchronous converter 50 s m ordered speed of the hydraulic generator -i-i. in response t o output signal ω go , asynchronous converter SO makes an ac voltage of the ordered fr quency. Since the hydraulic generator 44 is a synchronous type machine, the speed cf hydraulic generator 44 will be exactly proportional to the ac frequency of the 3-phase lines 10. Thus, setting tne frequency order co asynchronous converter 50 for its connection to 3-phase lines 10 is sufficient to implement speed regulation of hydraulic generator 44 (i.e., there is no need to measure shaft speed of hydraulic generator in the embodiment of Fig. IA) . The embodiment of Fig. 13 differs from the embodiment of Fig. IA by having control system 42B rather than control system 42A. In particular, control system 423 includes power transducer 78 and Hill Chart Updater 84 addition to predictive controller 76. Power transducer 73 monitors power on the three-phase lines connecting asynchronous converter 50 to AC power (utility) system ~: and outputs a signal P,„. to Hill Chart Updater 84. Hill Chart Updater 84 updates values stored look-up tables 94 and 95 (see Fig 6A and Fig. SB) based on on-line measurements. In this regard, Hill Chart Updater 34 utilizes the measured power output of asynchronous converter 16627 -11- 50 ( signal P„_.) , as well as the output signals (on lines 90 and 92) from predictive controller 75 and the signal .-._,... from water head transducer 25, co revise the H ll Char: information stored in tables 94 and 95 based cn actual historical information of the hydroelectric facility Thus, Hill Chart updater 34 is connected to receive the measured power signal ?,.„ from power transducer 73, as well as the gate position command oucputted on line 90 from predictive controller 76, the signal outputted on line 92 from predictive controller 76, and the h,„, signal outputted from water head transducer 25. Hill Chart Updater 84 outputs, to predictive controller 76, updating data as indicaced by a line marked "refinement" . The embodiment of Fig. 1C differs from the embodiment of Fig. IA by having control system 42C rather than control system 42A. In particular, control syscem 42C includes (in addition to predictive controller 76) a governor comprising an AC frequency controller 82 and adder 88. In the embodiment of Fig. IC, frequency controller 82 receives a signal f. c from asynchronous converter 50 the manner hereinafter described, the signal f. c being indicative of ac transmission frequency on che three-pnase lines connecting asynchronous converter 50 to AC power /16627 -12- (utility) system 72. Outpuc signal _,?., from AC frequency controller 82 is applied to a first (plus; input terminal cf adder 83. A second input (plus) terminal of adder 33 13 connected to receive the ordered power signal (denominated as P a , in the Fig. 1C embodiment) from control panel Adder 83 produces a signal P 0 wmch is applied as a first input to predictive controller 5 and which, m the embodiment of Fig. 1C, serves as the value P . , m Fig. 5 and Fig. 6A and Fig. 6B. As in the previous embodiments, the second input signal to predictive controller 76 of Fig. 1C is the signal h«__. applied from water head transducer 25. A first output of predictive controller 76 is a gate position command which is applied on line 90 to wicket gate controller 41. A second outpuc of predictive controller 76 of Fig. 1C (i.e., signal ω_ β ) is applied on line 92 co asynchronous converter 50. It should be understood that the features of the embodiment of Fig. IB and Fig. 1C are combinable a further embodiment, thereby including bcch Hill Chart update and ac frequency control a single embodiment Fig. 2 shows asynchronous converter 50 as including a variable frequency transformer 102 and a control system. The control system includes a fast speed control /16627 -13- unit 133,- a frequency transducer 30, and an adder 85. As described m more detail below wich reference to Fig 2, vanaole frequency transformer 102 is connected by 3-cr.asa lines RA, RB. RC to hydraulic generator 44 and by 3-phase lines SA, S3, and SC to utility system 72 These corresccr.d tt -phase lines denoted as 10 and 11, resDectivelv n "■- IA, 13, and IC. As shown in Fig. 2, variable frequency rotary transformer 102 includes boch a rotary transformer assembly 105 and a torque control unit 106 (also known as the rotor drive section) . Details of rotary transformer assembly _5 and torque control unit 106 are below described more detail in connection with Fig. 3. Frequency transducer 80 monitors ac frequency on the three-phase lines 11 connecting asynchronous converter 50 to AC power (utility) system and outputs the signal f. c to a negative input terminal of adder 86 (and to AC frequency controller 82 in the embodiment of Fig. IC) . Adder 86 receives the requesced rotational velocity signal for hydraulic machine 44 (signal _>- β on line 92) and outputs signal ω 0 to fast speed controller 108 An output signal -J, of adder 86, i.e., α, - _>- β - f, e is indicative of the desired rotational velocity of asynchronous converter 50 and accordingly is applied to asynchronous converter 50 /16627 - 14 - As also shown in Fig. 2, fast speed centre! unit 108 turn receives a signal ω r from speed transducer ill Fast speed control unit 103 receives che signal u, (from predictive controller 76 via adder 35) and outputs a drive signal T, to torque control unit 105. As shown in more detail in Fig 3, rotary transformer assembly 105 includes both a rotor suoassembiy 110 and a stator 112. Rotor subassembly 110 includes collector rings 114 (also known as slip rings) and rotor cage section 116. Three-phase lines RA, R3, RC leading from hydraulic generator 44 are connected to collector rings ii4, three-phase lines SA, SB, and SC leading to utility system 72 are connected to stator 112. Rotor subassembly no has speed transducer ill mounted proximate thereto for generating the angular velocity signal ω r indicative of the angular velocity of the rotor. As shown in Fig. 3 and understood by the man skilled in the art, in the illustrated embodiment rotary transformer assembly 105 is wound with a two-layer winding with sixty degree phase belts, with rotor windings being labeled as RA+, RC-, RB+, RA-, RC*, and RB- and stator windings labeled as SA+, SC-, SB+, SA-, SC-r, and S3- It should be understood that the invention is not limited to a sixty degree phase belt-wound system, rather the principles /16627 of the invention are applicable fcr rotary transformer assemblies of phase two and greater Rotor assemoly 110 is rctataoi_ about its axis R:< in both clockwise direction CW and counter-clockwise direction CCW Rotation of rotor assemoly 110 is effected by rotor drive section 106 Rotor drive section 105 is shown symbolically Fig. 2 as a cylindrical section mounted on rotor assembly 110. Thus, rotor drive section 105 of Fig 2 generally depiccs various alternative and different types of drive mechanisms for causing rotation of rotor assembly HO In some embodiments, rotor drive section 105 includes an actuator and some type of linkage (e.g , gearing and/or coupling) which interfaces w th rotor assembly 110 For example, in one embodiment rotor drive section 106 comprises a worm gear drive arrangement. In other embodiments, rotor drive section 106 comprises an actuator such as a stepper motor acting through a radial (e.g, spur) gear, a direct drive arrangement, a hydraulic actuator turning a gear on rotor assembly 110, or a pneumatic actuator turning a gear on rotor assembly 110 In yet other embodiments, the function of the torque concrol unit is accomplished by providing two sets of windings on ooth tne rotor and the stator of the rotary transformer assembly 105, a first set of windings on the rotor and stater having a different -15- nu ber of poles (e.g , 2 poles) than a second set of windings on the rotor and stator (e.g , 4 or more poles) In operation, an operator sets the power order input signal (signal P- in the embodiments of Fig. IA and Fig. 13,- signal P^ the embodiment of Fig. IC) accordance with a predetermined power requirement of utility system 72. Setting power order input signal (P 3 or 9 ^ , as the case may be) can be accomplished by adjusting a knob or inputting data at the operator control panel or operator workstation 74 to generate the signal indicative of the ordered power. Fast speed controller 108 receives both the requested or desired angular velocity signal ω 0 and a measured angular velocity signal ω r . The requested angular velocity signal ω β is generated by predictive controller 75 using its Hill Chart-based information. The measured angular velocity signal ω r is obtained from speed transducer ill. Fast speed controller 108 generates a drive signal (also known as the torque order signal TJ on line 134 so that ω r promptly equals ω 3 . The man skilled in the art knows how to operate conventional motor drivers as fast speed controller 108 to use signals ω r and ω 3 to generate the drive signal T β . /16627 - 17 - Thus, fast speed controller 108 operates to adjust the drive signal T β on line 134 to torque control unit 105 such chat the accual speed a r cc roccr assembly no follows the ordered speed ω 3 The closed-loop bandwidth of fast speed controller 108 should exceed the highest natural oscillatory frequency of rocor assembly no, including its reaction to the transmission network into which it is integrated, and is generally less tnan 100 rad/sec Typically, the natural modes of oscillation will range from about 3 rad/sec through 50 rad/sec, and are usually less than 30 rad/sec In connection with the σandwidth (speed of response) of fast speed controller 108, in the illustrated embodiment, a phase lag from a change in ordered speed ω_ to actual speed ω. of rotor assembly 110 is less than 90 degrees for sinusoidal disturbances Ensuring this bandwidth of response will in turn ensure that all such natural modes of oscillation will experience beneficial damping from the control system The magnitude of the drive signal T α on line 134 is used by rotor drive section 106 to increase or decrease the speed of rotor assembly 110 in order to achieve the desired speed of hydro macnme 44 As shown m Fig 3, drive signal T, on line 134 s applied co torque control amplifier 150 Power is supplied to torque control amplifier 150 by torque control power 6627 -13- scurce 152, whereby using drive signal T. on line 134 c.-.a corque control amplifier 150 outputs the three phase s -na s TA, TB, and TC to torque control unit 1C6. As used herein and in this art, TA refers collectively to TA * and TA-, T3 refers collectively to T3 * and TB-, and so forth. The angular positioning θ. of the rotor assembly 110 relative to the stator 112 is also shown in Fig. 3, t being understood from conventional practice chat θ. is zero when RA+ lines up exactly with 5A * . Power transfer through asynchronous controller 53 is understood with reference co simultaneously-filed United States Patent Application Serial No. 08/ , (attorney docket 17-GE-5546) entitled "INTERCONNECTION SYSTEM FOR TRANSMITTING POWER BETWEEN ELECTRICAL SYSTEMS", which is incorporated herein by reference for showing, e.g., various types of mechanisms utilized for rotor drive section 106. The real-time automatic governor for asynchronous converter 50, accomplished by Ac frequency controller 32 and adder 88, provides an automatic adjustment of order power input signal P J(J depending upon actual real-time requirements of AC Power System 72. For example, if AC Power System ' 2 were, at any moment, not receiving enough power despite tne order power signal P αo , the frequency on lines 11 would decrease and such decrease would be sensed by frequency 7/16627 -19- transducer 80 and compensated for cy predictive controller 76 response to signal Pj so that a greater power level than that evoked by signal ?„„ would result. Conversely, _: too much power were being supplied to AC Power System 72, the frequency on lines 11 would increase and such increase would be sensed by frequency transducer 30 and comcensaced for by predictive controller 75, so that a lesser power level than that evoked by signal F .α would result. In the embodiment of Fig. IC, the signal ?, to predictive controller 76 is indicative of the requested power level, rather than the order power signal P 00 ;P, being a modification of P 00 as explained above) . Thus, the present invention accomplishes -/ariable speed with the conventional direct-current field winding cr. the main generator 44, varying the frequency of the ac current flowing in the stator of the main generator deviating from the nominal frequency of the AC power system 72 by an amount needed to achieve the desired speed variation (e.g., 55 Hz would yield a 110% speed on a generator nominally operated at 50 Hz) . Moreover, the 16627 - 20 - present invention achieves its objective of optimum hydraulic efficiency by measurement of water head and ac transmission syscem frequency only, with an open-iocp concrol function based upon a "Hydraulic Hill char t " computed off line. As another advantage, power-system frequency is controlled by measuring ac transmission system frequency and adjusting the power order to the mam control function Damping of power system oscillations is also provided via the fast speed controller 108. Converter 50 thus can easily be used co retrcfic existing hydrogenerator facilities. Limits of speed adjustability of each hydrσgeneracor facility w ll depend cn mechanical stresses and the ability of other system components to perform their functions. At least one generator in any given dam complex can be equipped with converter 50, or just selected dam sites along a river requiring extra concrol capability. Moreover, converter 50 provides a significant tool for power authorities who manage water resources By uncoupling flow race (through the turbine) with power demand, water levels can De adjusted accurately without wasting energy. Such accurate adjustment includes the 7/16627 li¬ ability to adjust for flood and/or drought conditions in ¬ different regions of the same river. Converter 50 also addresses the issue of pumped storage concrol. Pumped storage nydroeleccric typically involves a two reservoir system, one reservoir being at a higher elevation and another reservoir being at a lower elevation. ater is pumped to the higher reservoir, storing its potential energy until utilities encounter extraordinary peak demand conditions. The water is then released through hydroturbines to meet this peak demand. Severe drainage of the upper reservoir as occurs ac peak demand requires pumping (at an off-peak time) of water back from the lower reservoir to the higher reservoir. During low reservoir conditions, converter 50 provides the advantage of fast response and reduced operating speed. By running slightly slower and using a smaller reserve margin, power authorities can optimize water conservation while maintaining a load response rate equal to their water gating rate. Benefits of the present invention include lower environmental stress (saving fish, minimizing erosion, etc ) and superior wacer level concrol, parcicularly in mulci- basin systems. This concrol improves usefulness of wacer supply ooch for recreational and agricultural aspects, sucn as irrigation. 6627 - 22 - While the invention has been particularly s own and described with reference to tne preferred emoodi-ents thereof, it will be understood by those skilled m the art that various alterations form and detail may be made therein without departing from the spirit and scope c: tr. invention. For example, whereas the foregoing description a supply electrical system has been illustrated as being connected to collector rings 114 and a receiver electrical system has been illustrated as being connected to stator 112, it should be understood that these illustrated connections can be reversed.

Claims: 16627 - 23 - The embodiments cf the invention m which an exclusive property or privilege 13 claimed are defined as follows .- 1. A method of transmitting electrical power from a hydro- turbine unit to an electrical utilization system, the method comprising: obtaining a signal indicative of water head, using the signal indicative of water head to concrol speed and gate position of a variable speed hydro- turbine unit to yield a requested power level to the electrical utilization system. 2. The method of claim 1, wherein controlling the speed of the variable speed hydro-turbine unit involves using the signal indicative of wacer head to access a memory wherein Hydraulic Hill Chart information is stored. 3. The method of claim 1, further comprising updating the memory wherein the Hydraulic Hill Chart informacion is scored. 7/16627 -24- 4. The method of claim i, furchεr comprising: obtaining a signal mdicacive of ac transmission frequency co the electrical utilization system, and also using the signal indicative of ac transmission frequency co the electrical utilization system to concrol he oucpuc power of the variable speed hydrc- turb e unit. 5. The method of claim l, wherein the step of using the signal indicative of water head to concrol speed and gate position of a variable speed hydro-turbine involves controlling rotor speed of an asynchronous rotary converter connected between the hydro-turbine unit and the electrical utilization system. 6. An interface for coupling a hydro-turbine unit to an electrical utility, the interface comprising.- a rocary converter coupled co the hydro-turbine unit for receiving a hydro-turbine output electrical power generated by the hydro-turbine unit; a controller which operates the rotary converter so that a requested output electrical power level is obtained from the hydro-turbine unit for the electrical utility, the controller using a signal indicative of water head to concrol speed and gace posicion of che hydro-turbm.2 unit to yield the requested power level to the electrical utilit . 16627 ■ ± x - 7 The interface of claim 6 , wherein tne rotary converter s coupled to the hydro-turbine such chat ac frequency ct the rotary converter is proportional to rotational velocity of the hydro-turbine machine. 8. The interface of claim 6, wherein che controller includes a processor which uses che signal indicative of water head to access a memory wherein Hydraulic Hill Chart information is stored. 9. The interface of claim 8, further comprising a Hill Chart updater to update values stored in the memory wherein Hydraulic Hill Chart information is stored. 10. The interface of claim 6, wherein che controller also uses a signal indicative of ac transmission frequency to tne electrical utility to concrol che output power of the rotary converter for yielding the requested power level to the eleccrical utility. 6627 -26- n The interface of claim 6, wherein che rotary conver t er comprises one of a rotor and a stator connected to receive che hydro-turbine output electrical power, che other of the rotor and the stater being connected so chat the converter output electrical power is extracted therefrom, an actuator for rotating the rotor, wherein the controller is responsive to the signals for controlling the actuator whereby the rotor is bidirectionally rotated at a variable speed 12 A hydroelectric power generation system which generates electrical power for an electrical utilization system, the hydroelectric power generation system comprising a hydro-turbine unit which is driven by water flow to generate hydro-turbine output electrical power, a rotary converter coupled co receive che hydro- curbme output electrical power, a controller which operates the rotary converter so that a requested converter output electrical power level is obtained from the hydro-turbine unit, the controller using a signal indicative of water head to control speed and gate position of the hydro-turbine unit for yielding the requested output power level to the utilization system -27- 13. The system of claim 12, wherein che rotary converter is coupled co che hydro- urbine such chat ac frequency of the rotary converter is proportional to rotational velocity of the hydro-turbine machine. 14. The system of claim 12, wherein the controller includes a processor which uses the signal indicative of water head to access a memory wherein Hydraulic Hill Chart information is stored. 15. The system of claim 14, further comprising a Hill Chart updater to update values stored in the memory wherein Hydraulic Hill Chart information is stored. 16. The system of claim 12, wherein che controller also uses a signal indicative of ac transmission frequency co che electrical utility to concrol che output power of the rotary converter for yielding the requested power level to the electrical utility. 17. The system of claim 12, wherein che rocary converter comprises: one of a rotor and a stator connected to receive che hydro- urbine output electrical power,- the other of the rotor and the stator being connected so that the converter output electrical power 13 extracted therefrom,- 6627 -28- an actuator for rotating the rotor, wherein the controller is responsive co che signals for controlling the actuator whereby the rotor is bidirectionally rotated at a variable speed. 13. A hydroelectric power generation system which generates electrical power for an electrical utilization system, the hydroelectric power generation system comprising: a hydro-curbine unit which is driven by wacer flow to generate hydro-turbine output electrical power,- a rotary converter coupled co the hydro-turbine and which transmits the hydro-turbine output electrical power co the eleccrical utilization system, the rotary converter comprising: a rotor and a stator, one of the rotor and the stator being coupled to the hydro-turbine unit and the other of the rotor and stator being coupled co the electrical utilization system,- a controller which takes into consideration ac frequency of the hydro-turbine output eleccrical power for generating a signal for controlling rotational speed of the rotor relative to the stator. 7/16627 -29- 19 The system of claim 13, wherein the controller comprises . a frequency transducer whicn monitors ac frequency of che eleccrical utilization system and genera t es a signal f. c indicative thereof,- and means for using the signal f, e generated by the frequency transducer to modify a signal indicative ω 30 of a requested rotational velocity of che hydro-turbine unit, the signal modifying means outputt g a modified signal ω β for use in controlling rotational speed of the rotor relative to the stator. 20. An interface for coupling a hydro-turbine unit to an eleccrical utility, the incerface comprising: a rotary converter coupled to the hydro-turbine and which transmits eleccrical power co the electrical utilization system, the rotary converter comprising: a rotor and a stator, one of the rotor and the stator being coupled co the hydro-turbine unit and the other of the rotor and stator being coupled co che eleccrical utilization system,- a controller which cakes meo consideration ac frequency of che output eleccrical power for generating a signal for controlling rotational speed of the rotor relative to the stator. 6627 - 30 - 21. The interface of claim 20, wherein che controller comprises .- a frequency transducer which monitors az frequency of the electrical utilization system and genera t es a signal f, e indicative thereof,- and means for using the signal f 4C generated by the frequency transducer co modify a signal indicative ω 3β of a requested rotational velocity of the hydro-turbine unit, the signal modifying means outputting a modified signal ω, for use in controlling rotational speed of the rotor relative to the stator.

Inventors: ARDLEY GLENN HENRY, LARSEN EINAR VAUGH, MCLAREN DONALD GORDON, RUNKLE MARK ANDREW, WEEBER KONRAD, ARDLEY, GLENN, HENRY, LARSEN, EINAR, VAUGH, MCLAREN, DONALD, GORDON, RUNKLE, MARK, ANDREW, WEEBER, KONRAD
Applicants: GEN ELECTRIC, GENERAL ELECTRIC COMPANY
Application year: 1996
Main classification: F01D15
IPC codes: H02P9