Improved Reversible Pump-Turbine Installation

Abstract

The present invention is a reversible pump-turbine installation position in a vertical shaft instead of in a conventional underground powerhouse or deep concrete powerhouse. The required plant cavitation coefficient may be achieved by simply boring a vertical shaft to the required depth rather than routing the water flow to and from a deeply buried powerhouse. A pneumatically controlled pressure relief valve may be incorporated into this invention.

Claims

1. A pumped storage system comprising: an upper water storage basin, a lower water storage basin, a reversible pump-turbine connected to said upper water storage basin by a penstock conduit and also connected to said lower water storage basin by means of a tail water conduit, a motor-generator operably connected to said pump-turbine; wherein said pump-turbine comprises multiple stages, and wherein said pump turbine is positioned in a vertical shaft at an elevation below the surface of said lower water storage basin, and wherein said pump-turbine is axially removable from said vertical shaft.

2. (canceled)

3. A pumped storage system as described in claim 1, wherein said penstock conduit and said tail water conduit are coaxially positioned in said vertical shaft above said pump-turbine.

4. (canceled)

5. A pumped storage system as described in claim 1, wherein said motor-generator is positioned below said pump-turbine.

6. (canceled)

7. A pumped storage system as described in claim 3, wherein said coaxial conduits comprise an inner conduit and an outer conduit, and further comprising a removable manifold for directing water in said inner conduit to said lower water storage basin and for directing water from said upper water storage basin to said penstock conduit.

8. A pumped storage system as described in claim 7, wherein said manifold further comprises a pneumatically controlled pressure relief valve for reducing surge pressure in said penstock conduit.

9. A pumped storage system as described in claim 1, further comprising a hoisting piston positioned below said pump-turbine for selectively raising and lowering said pump-turbine in said vertical shaft.

10. A pumped storage system having an upper water storage basin, a lower water storage basin, and a reversible pump-turbine connected to said upper water storage basin by a penstock conduit and also connected to said lower water storage basin by means of a tail water conduit, wherein said pump-turbine is positioned in a vertical shaft at an elevation below the surface of said lower water storage basin; wherein said pump-turbine is axially removable from said vertical shaft; wherein said conduits are coaxially positioned in said vertical shaft.

11. A reversible pump-turbine comprising: a submersible motor-generator. wherein said motor-generator is located beneath one or more pump-turbine stages, and wherein said reversible pump-turbine is located in a vertical shaft from which it is removable.

12-13. (canceled)

14. A reversible pump-turbine as described in claim 11 further comprising a removable manifold fixed to the top of the shaft during operation.

15. A reversible pump-turbine as described in claim 14 wherein the removable manifold includes a pressure relief valve for relieving excess head pressure to the tailwater conduit.

16. A reversible pump-turbine as described in claim 15 wherein the pressure relief valve is comprised of an elastomeric diaphragm held by controlled gas pressure against one or more orifices containing headwater pressure.

17. A reversible pump-turbine as described in claim 11 wherein the motor-generator is located above the turnout connecting the headwater to the vertical shaft.

18. A reversible pump-turbine as described in claim 11 wherein the pump-turbine is comprised of multiple stages.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 is a schematic of a conventional (prior art) pumped storage facility.

[0016] FIGS. 1b and 1c are sectional elevation drawings of a conventional pump-turbine.

[0017] FIG. 2 is a schematic of a pumped storage facility in accordance with the present invention.

[0018] FIG. 3 is a section through the meridional plane of a multistage pump of prior art.

[0019] FIG. 3a is an elevation view of the pumped storage facility of FIG. 3a shown with the pump-turbine assembly partially removed.

[0020] FIGS. 4a and 4b are sectional elevations of a pressure relief valve configured for use with the present invention.

[0021] FIG. 5a-c are sectional elevation drawings of a reversible pump-turbine in accordance with the present invention.

[0022] FIG. 6 is a cutaway rendering of a reversible pump-turbine and associated pumped storage facility in accordance with the present invention.

[0023] FIG. 7 is a cutaway view of an elbow connection to the tailrace tunnel with an inflatable seal to secure and seal it in accordance with the present invention.

[0024] FIG. 8 is a sectional elevation drawing of a pump-turbine installation with the vertical borehole collocated with the headworks in accordance with the present invention.

[0025] FIG. 9 is a sectional elevation drawing of a pump-turbine installation with the vertical borehole collocated with the tailrace portal in accordance with the present invention.

[0026] FIG. 10 is a sectional elevation drawing of a pump-turbine installation with the vertical borehole located between the headworks and the tailrace portal in accordance with the present invention.

[0027] FIG. 11 is a sectional elevation drawing of a pump-turbine installation with the vertical borehole located in association with an underground pressured water storage cavity that serves as the upper reservoir.

[0028] FIG. 12 is a schematic of a pump in accordance with the present invention in association with an air/water accumulator, most likely underground, and a gas turbine.

[0029] FIG. 13 is a schematic of a pump in accordance with the present invention in association with an air/water accumulator, most likely underground, and a gas turbine, wherein the air may be nearly isothermally compressed with the aid of water spray cooling.

[0030] FIG. 14 illustrates a tailrace connection elbow in accordance with the present invention that incorporates an inflatable seal that also serves as an adjustable pressure relief element. The inflatable seal (63) features a flow separation control fin 51 to reduce vibration during operation.

[0031] FIG. 15 illustrates a pumped storage installation in accordance with the present invention including a a tailrace connection elbow.

[0032] FIG. 16 illustrates a pumped storage installation in accordance with the present invention including a tailrace connection elbow and a penstock entering the borehole at an elevation higher than the tailrace tunnel.

[0033] FIG. 17 illustrates a pumped storage installation in accordance with the present invention including a tailrace connection elbow.

[0034] FIG. 18 illustrates a pumped storage installation in accordance with the present invention including a tailrace connection elbow.

[0035] FIGS. 19a and 19b are meridional plane sections of a multistage pump impeller in accordance with the present invention.

[0036] FIG. 19c is and end on view looking into the discharge edge of the impeller of FIG. 19b.

[0037] FIG. 20 is a plan view schematic of 3 pump turbines installed in association with a single penstock and a single tailrace tunnel.

[0038] FIG. 22a is a pump turbine installation including a pressure relief valve.

[0039] FIG. 22b is a schematic of a torque key positioned at the bottom of a bore hole for the purpose of preventing unintended rotation of the pump-turbine.

[0040] FIG. 23 is a pressure relief valve in accordance with the present invention.

[0041] FIGS. 24a and 24b is a pressure relief valve in accordance with the present invention shown closed and open respectively.

[0042] FIGS. 25a and 25b is a pressure relief valve in accordance with the present invention shown closed and open, respectively.

[0043] FIGS. 26a and 26b show a pressure relief valve in accordance with the present invention shown closed and open respectively.

[0044] FIGS. 27a and 27b show an installation of multiple pump-turbine/motor generators in a single bore hole.

[0045] FIG. 28 shows schematically one version of the pump turbine of the present invention.

[0046] FIG. 29 shows another version of the pump turbine of the present invention.

[0047] FIG. 30 shows another version of the pump turbine of the present invention incorporating a cylinder gate rather than wicket gates.

[0048] FIGS. 31-37 show various installation alternatives.

[0049] FIGS. 38-43 show various embodiments of a reversible pump turbine

[0050] FIGS. 44a-b show a flow inverter section.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] Referring to FIGS. 1a, 1b, and 1c, a conventional pumped storage plant with a reversible pump-turbine is shown. There are several notably expensive features in such a conventional installation. These include; [0052] 1) A surge shaft that is typically needed to relieve waterhammer that can result from a load rejection. [0053] 2) An underground powerhouse below tailwater level. Such a powerhouse is expensive to construct and is at risk of flooding due to human error or component failure. Flooding of an underground powerhouse is a hazard to the facility itself as well as to its operators. [0054] 3) The penstock and tailrace conduit must be routed, at great expense to the same low elevation as the powerhouse itself.

[0055] Referring to FIG. 3a and FIG. 3b, a reversible pump-turbine installation in accordance with the present invention is shown. No underground powerhouse is required. Instead, a vertical borehole or shaft 4 allows the pump-turbine and motor-generator assembly 1 to be installed, removed for maintenance as needed, and reinstalled, while providing the desired low height-of-setting of thee unit below tailwater. The height of setting must be sufficiently low that the plant cavitation coefficient (plant sigma) is greater than the critical cavitation coefficient (critical sigma), the cavitation coefficient being defined as the ratio of absolute pressure at the low-pressure side of the runner divided by the vapor pressure of water at the temperature of the water. Shaft 16 connects submersible motor-generator 8 to pump-turbine stages 9, 10, 11, and 12. Vertical tailwater conduit 5 connects to diffuser 14 above the point of entry of penstock 2. Pressure relief valve 7 is preferably mounted to removable manifold 6. Removable manifold 6 bolts down to foundation 13 and connects to tailrace conduit 3 at flange 15a. Tailrace conduit 3 leads to the lower reservoir not shown. It should be noted that the number of stages may be adjusted according to head, height of setting, speed, installation rating and other factors. Penstock 2 connects to upper reservoir 70. Tailrace conduit 3 connects to the lower reservoir 71. Water flows through outer annulus 17 of borehole 4 toward the upper reservoir 70 as a pump and towards the pump turbine 43.

[0056] It should be noted that the removable portion may be further divided into conveniently separable subassemblies 6, 7, 14 and 5. For example, the manifold 6 might be lifted off first, the vertical portion of the tailrace conduit 5 might be lifted next, and the pump-turbine stages 9, 10, 11, and 12 might be lifted last along with the motor-generator 8. In the case of a motor generator on top, the stator might be left in place while the rotor, shaft, and balance of the assembly might be lifted out last.

[0057] Referring to FIGS. 4a and 4b, a cross section of a pressure relief valve suitable of use in conjunction with the present invention is shown in its opened and closed positions respectively. Diffuser 14 is connected to ribs 25. Ribs 25, ring 23, and ring 24 together radially support bladder 18 on its inner diameter surface when its inflation pressure is greater than the pressure in shaft 17. Inflatable bladder 18 is supported from below by flange 26 and on its OD by enclosure 7. The air pressure in bladder 18 may be precisely adjusted to just stop leakage from shaft 17 into manifold 6 (at tailwater pressure).

[0058] Referring to FIGS. 5a and 5b a sectional elevation of a pump-turbine in accordance with the present invention is shown. Runner 27 is designed around a toroidal flow path wherein water reverses direction by approximately 180 degrees in the meridional plane. Wicket gates 28 make up an axial flow distributor. Turbine diffuser 29 recovers turbine runner exit energy. Stay vanes 30 provide mechanical support to the distributor hub 31, turbine diffuser 29 as well as wicket gate servo system 32. Generator 33 is preferably located below the turbine. Hoisting piston 34 may be used to raise and lower, using water pressure, the entire pump-turbine assembly with connected draft tube segments, pressure relief valve and elbow. Hoisting piston 34 may incorporate upper seal ring 35 and lower seal ring 36 to maintain a seal while passing across the tailrace connection.

[0059] Hollow shaft 72 may be used as a heat pipe evaporator in conjunction with the runner 27 serving as a condenser. Electrical connector 73 engages electrical receptacle assembly 74 when the machine is lowered. Shifting rings 75 and 76 provide torque to actuate wicket gates 28.

[0060] Borehole 4 is associated with rock face 77, grout 78 and steel liner 79.

[0061] Shaft seal assembly 80 keeps the generator enclosure dry.

[0062] Referring to FIG. 6, Piston assembly 34 supports generator 33 and pump-turbine 37 during raising and lowering. Valve 38 may be used to shut off water from penstock 39. Tailrace conduit 40 connects to tailwater. Cover assembly 41 is removable.

[0063] Referring to FIG. 6, valve 42 may be used to fill vertical shaft 4 during hydraulic raising and lowering of pump-turbine-motor-generator assembly 43 with attached pipe, elbow, and pressure relief assemblies 44, Lower portal 45 serves to launch TBM during construction phase and serves as pumping inlet works. Headworks 47 serves as upper portal during construction and as service platform during maintenance. Crane 48 may be used to disassemble draft tube segments, elbow assembly and pressure relief valve from pump-turbine for maintenance.

[0064] Referring to FIG. 7 an elbow assembly 49 is shown. Inflatable seal 50 seals the upper end. Inflatable seal 51 closes the lower end. Elbow 52 directs flow to the tailrace conduit. Spool 53 travels with the pump-turbine during maintenance moves.

[0065] Referring to FIG. 8 an installation is shown wherein the machine shaft 54 is located under the headworks 55.

[0066] Referring to FIG. 9, the machine shaft 54 is located below the tailrace portal 56.

[0067] Referring to FIG. 10, machine shaft 54 is located at a location between the headworks 55 and tailrace portal 56.

[0068] Referring to FIG. 11, Machine shaft 54 provides a connection to pressurized reservoir 58 as well as to tailrace tunnel 59.

[0069] Referring to FIG. 12 a pressurized water reservoir 58 is shown in conjunction with a pressurized air column 59. Pump or pump/turbine 60 may be in accordance with this invention or may be conventional. Air 59 may be fed to a gas turbine generator set 61.

[0070] Referring to FIG. 13, spray cooling of the air being compressed may be used to provide isothermal air compression.

[0071] FIGS. 6, 7, 16, and 17 depict one of many possible construction sequences.

[0072] Referring to FIG. 17, another embodiment is shown wherein inflatable seal 63 may also serve as a pressure relief valve.

[0073] Referring to FIG. 18, a combined seal and PRV 63 positioned in machine shaft 54 is shown in conjunction with elbow 52 and tailrace conduit 40. Machine shaft liner 64 is shown.

[0074] Referring to FIG. 17, another embodiment is shown wherein inflatable seal 63 may also serve as a pressure relief valve.

[0075] Referring to FIG. 18 another embodiment is shown with vanes 65 in elbow 52.

[0076] Referring to FIGS. 19a and 19b a runner for a pump or reversible pump turbine is shown wherein flow is directed along a smooth sinusoidal path within the meridional plane. Blades (vanes) impart circumferential acceleration vector and acceleration vectors within meridional plan to guide water through water passageway. Blade sequences may be normal to vector sum. The larger impellar is more efficient and provides higher head per stage. Impellars may be best made by 3D printing.

[0077] Referring to FIGS. 21-23, various pressure relief valve configurations are shown.

[0078] Referring to FIG. 24 splitter vanes are used.

[0079] Referring to FIG. 27, multiple pump turbines are shown sharing a common penstock 2 and tailrace conduit 3.

[0080] Referring to FIGS. 27A and 27b, multiple submersible pump-turbines 62a-62f, installed together in the same machine shaft 54 are shown.

[0081] FIGS. 28 through 30 show pump-turbines configured for installation on a bulkhead in a common machine shaft.

[0082] Referring to FIG. 31, a medium/high voltage permanent-magnet motor/generator 95 and battery storage array 98 are connected to a utility grid 90 via a single cascade multilevel power converter. The power converter comprises a phase-shifting input transformer 92, power cells incorporating a regenerative-capable front-end 93, isolated DC buses 95, and load-side inverters 94. Each power cell DC bus is connected to a battery bank 98 via a disconnect switch 97. The individual DC bus 96 voltages are actively managed during operation to charge or discharge the battery banks 98 independently of power consumption or generation by the motor/generator 95.

[0083] Referring to FIG. 32, a low-voltage permanent-magnet motor/generator 95 and battery storage array 98 are connected to a utility grid 90 via a single two-level power converter. The power converter comprises an active front-end with line-side reactor 93, an intermediate DC bus 96, and a motor-side two-level inverter 94. The power converter is connected to the grid through a disconnect 100 and step-up transformer 99. The power converter DC bus 96 is attached to a battery array 98 through a disconnect switch 97. The DC bus 96 voltage is actively managed during operation to charge or discharge the battery array 98 independently of power consumption or generation by the motor/generator 95.

[0084] Referring to FIG. 33, a permanent-magnet motor/generator 95 and battery storage array 98 are connected to a utility grid 90 using parallel and independent power converters. The converters may be connected using individual disconnects 91 incorporating protective functions. The motor/generator 95 is connected using a regenerative AC/AC power converter 102. The battery array 98 is connected through DC bus disconnect(s) 97 to a grid-tie inverter 101. A step-up transformer 99 increases inverter 101 output to grid voltage. Optionally, a disconnect 100 is placed between transformer 99 and the battery inverter 101.

[0085] Referring to FIG. 34, a medium/high voltage doubly-fed induction machine 103 and battery storage array 98 are connected to a utility grid 90. The rotor windings of the electric machine are connected to a cascade multi-level AC/AC drive with connected battery storage as described in FIG. 31. The stator windings of the electric machine are connected to the grid through a disconnect 104.

[0086] Referring to FIG. 35, a medium/high voltage doubly-fed induction machine 103 and battery storage array 98 are connected to a utility grid 90. The rotor windings of the electric machine are connected to a low-voltage two-level AC/AC drive with connected battery storage as described in FIG. 32. The stator windings of the electric machine are connected to the grid through a disconnect 104.

[0087] Referring to FIG. 36, a medium/high voltage doubly-fed induction machine 103 and battery storage array 98 are connected to a utility grid 90. The rotor windings of the electric machine are connected to regenerative AC/AC drive 102. The stator windings of the electric machine are connected to the grid through a disconnect 104. The battery storage array is connected to a separate and independent DC/AC inverter 101 as described in FIG. 33.

[0088] Referring to FIG. 37, multiple medium/high voltage permanent-magnet motor/generators 95 are connected to a utility grid 90 in an arrangement that allows either direct synchronous connection using direct on-line contactors 105 in conjunction with forward/reverse selecting contactors 106/107, which are interlocked to prevent simultaneous closure. Regenerative power converters 102 can be used to bring the electric machines up to synchronous speed in either the pumping or generating mode, or to operate at variable other-than-synchronous speeds. Phase-shift input transformers 92 connect the active front-end of the converters 102 to the grid via disconnects 91. A matrix of disconnects 108 allows any of the electric machines to be operated or started using any of the power converters.

[0089] As can be easily understood from the foregoing, the basic concepts of the present invention may be embodied in a variety of ways. It involves both water control and actuator techniques as well as devices to accomplish the appropriate water control or actuation. In this application, the water control techniques are disclosed as part of the results shown to be achieved by the various devices described and as steps which are inherent to utilization. They are simply the natural result of utilizing the devices as intended and described. In addition, while some devices are disclosed, it should be understood that these not only accomplish certain methods but also can be varied in a number of ways. Importantly, as to all of the foregoing, all of these facets should be understood to be encompassed by this disclosure.

[0090] The discussion included in this application is intended to serve as a basic description. The reader should be aware that the specific discussion may not explicitly describe all embodiments possible; many alternatives are implicit. It also may not fully explain the generic nature of the invention and may not explicitly show how each feature or element can actually be representative of a broader function or of a great variety of alternative or equivalent elements. Again, these are implicitly included in this disclosure. Where the invention is described in device-oriented terminology, each element of the device implicitly performs a function. Apparatus claims may not only be included for the device described, but also method or process claims may be included to address the functions the invention and each element performs. Neither the description nor the terminology is intended to limit the scope of the claims included in this patent application.

[0091] It should also be understood that a variety of changes may be made without departing from the essence of the invention. Such changes are also implicitly included in the description. They still fall within the scope of this invention. A broad disclosure encompassing both the explicit embodiment(s) shown, the great variety of implicit alternative embodiments, and the broad methods or processes and the like are encompassed by this disclosure and may be relied upon for the claims for this patent application. It should be understood that such language changes and broad claiming is accomplished in this filing. This patent application will seek examination of as broad a base of claims as deemed within the applicant's right and will be designed to yield a patent covering numerous aspects of the invention both independently and as an overall system.

[0092] Further, each of the various elements of the invention and claims may also be achieved in a variety of manners. This disclosure should be understood to encompass each such variation, be it a variation of an embodiment of any apparatus embodiment, a method or process embodiment, or even merely a variation of any element of these. Particularly, it should be understood that as the disclosure relates to elements of the invention, the words for each element may be expressed by equivalent apparatus terms or method termseven if only the function or result is the same. Such equivalent, broader, or even more generic terms should be considered to be encompassed in the description of each element or action. Such terms can be substituted where desired to make explicit the implicitly broad coverage to which this invention is entitled. As but one example, it should be understood that all actions may be expressed as a means for taking that action or as an element which causes that action. Similarly, each physical element disclosed should be understood to encompass a disclosure of the action which that physical element facilitates. Regarding this last aspect, as but one example, the disclosure of a means for actuating or an actuator should be understood to encompass disclosure of the act of actuatingwhether explicitly discussed or notand, conversely, were there effectively disclosure of the act of actuating, such a disclosure should be understood to encompass disclosure of an actuator and even a means for actuating. Such changes and alternative terms are to be understood to be explicitly included in the description.

[0093] Any acts of law, statutes, regulations, or rules mentioned in this application for patent; or patents, publications, or other references mentioned in this application for patent are hereby incorporated by reference. In addition, as to each term used it should be understood that unless its utilization in this application is inconsistent with such interpretation, common dictionary definitions should be understood as incorporated for each term and all definitions, alternative terms, and synonyms such as contained in the Random House Webster's Unabridged Dictionary, second edition are hereby incorporated by reference. Finally, all references listed in the list of References To Be Incorporated By Reference In Accordance With The Patent Application or other information statement filed with the application are hereby appended and hereby incorporated by reference, however, as to each of the above, to the extent that such information or statements incorporated by reference might be considered inconsistent with the patenting of this/these invention(s) such statements are expressly not to be considered as made by the applicant(s).

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