Improved reversible pump-turbine installation

Abstract

To provide a reversible pump-turbine used for the storage of electrical energy. [Solution] The present invention establishes the required plant cavitation coefficient by locating a reversible pump-turbine with a motor-generator in a nearly vertical borehole, generally well below the tailwater level. The present invention is a reversible pump-turbine installation location in a vertical shaft as an alternative to conventional underground power plants or deep concrete power plants. The required plant cavitation coefficient can be achieved simply by drilling a vertical shaft to the required depth, rather than routing water flow to and from a deeply buried power plant. A pneumatically controlled pressure relief valve can be incorporated into the present invention.

Description

[Background technology]

[0001] The present invention relates to a reversible pump-turbine used for the storage of electrical energy. 2a Conventional pumping plants, such as that shown in Figure 1, generally use underground power plants and provide sufficient absolute pressure at the runner to prevent destructive cavitation. The depth of the runner may be, for example, 100 meters below the discharge. Constructing and maintaining such underground plants is expensive, and even for smaller plants, the costs do not decrease with size. Therefore, there are very few pumping plants below 100 MW in North America. A cross-sectional elevation of a typical conventional pump-turbine is shown in Figure 1. 2a A prior art pump-turbine flowpath with a 90° bend angle in the meridian plane is shown in FIG. 2b , which is similar to the flow path in the meridian plane of a conventional Francis turbine. The present invention relates to dedicated turbines and pumps and reversible pump-turbines. For prior art multi-stage pumps, the relationship between the impeller and the diffuser in the meridian plane is shown in FIG. (Not specified) In the figure, the acceleration to the fluid imparted by the runner (impeller) is outward and downward, which in this case results in an unnecessarily small runner tip diameter compared to the maximum channel diameter occurring in the diffuser. This unnecessarily small diameter results in a limited head difference across each stage, and therefore more stages and lower overall efficiency. Summary of the Invention [Means for solving the problem]

[0002] The present invention establishes the required plant cavitation coefficient by locating a reversible pump-turbine with motor-generator in a substantially vertical borehole, generally well below the tailwater level. The reversible pump-turbine with motor-generator will be referred to herein simply as the "pump-turbine" or "machine." The term "borehole" rather than "shaft" is used herein to avoid confusion with the rotating shaft of the pump-turbine located therein.

[0003] Conventional pumping equipment positions the runner well below the tailrace depth to suppress cavitation while maintaining high engine power and specific speed. The critical cavitation coefficient for a reversible pump-turbine is higher than that for either the turbine or the pump because the hydraulic cross section is compromised between pumping and power generation and is not optimized for either. Locating the runner below the tailrace traditionally required deep and expensive excavation, regardless of machine size and rating. Excavation and underground construction costs were prohibitive even for small installations, e.g., below 100 MW. Suitable sites for large-scale installations are limited by geology, geography, competing land uses, and sufficient transmission lines. Although many suitable smaller sites exist, existing reversible pump-turbines, even when scaled down in size and rating, still require prohibitive excavation and construction costs.

[0004] The proposed configuration utilizes a simple and inexpensive borehole, perhaps one to three meters in diameter, and positions a high-specific-speed, reversible pump-turbine well below the discharge depth to suppress cavitation. Such boreholes are routinely drilled as general-purpose construction work at reasonable cost. For example, steel liners and conduits for pumping, electrical cables, and control cables can be routed into place within the borehole. Pump-turbines adapted for this type of installation can be configured as single-stage machines or as multi-stage machines utilizing specially configured "diffuser bowls" similar in function to those used on multi-stage submersible pumps. These pump-turbines would typically not use conventional volute casings. Thus, the stages of these pump-turbines can be stackable, allowing a standard hydraulic design to be used over a wide range of head conditions. The use of standard pump-turbine stages is further facilitated by the fact that the required plant cavitation coefficient can be achieved simply by establishing the required vertical borehole depth. Compared to conventional underground power plant pump-turbine installations, there is less need to design and manufacture site-specific machinery, which would be prohibitively expensive in most locations along with the installation of small pumped storage hydroelectric plants, and neither headrace conduits nor tailraces need to be transported to extraordinary depths. The use of standard components results in an increased quantity of similar parts at reduced cost. The reduced cost, in turn, allows a greater number of projects to be built using increased part quantities.

[0005] Water flow to and from the reversible pump-turbine may be through a coaxial water conduit located within the shaft above the pump-turbine assembly. The associated motor-generator is submersible and, in certain preferred embodiments, may be located below the pump-turbine. Locating the motor-generator below the pump-turbine allows for a larger diameter, and therefore more economical, motor-generator for a given borehole size. Allocating substantially all of the borehole cross-sectional area to water transport (up and down) rather than to space for the motor-generator allows for the maximum power rating for a given diameter of the borehole.

[0006] The generator may alternatively be located outside the waterway and connected to the runner with a shaft. Such an arrangement may be cheaper than providing an underground power plant large enough to incorporate a volute casing, while allowing the use of readily available air-cooled generators.

[0007] In a preferred embodiment, a removable manifold may be used to connect the inner pipe to the discharge and the outer pipe to the headrace leading to the draw. It is generally more efficient to connect the smaller diameter pump inlet / turbine outlet to the smaller of the two coaxial pipes, while connecting the larger pump outlet / turbine inlet to the larger of the two coaxial pipes. Alternative embodiments of the present invention may utilize a different arrangement, as may be the case when multiple pump-turbines are installed, for example, on bulkheads within a common borehole. The removable manifold may include an integrated pneumatically controlled pressure relief valve. This integrated pressure relief valve would itself reduce civil engineering costs by eliminating the need for a pressure relief shaft and by reducing headrace surge pressures and headrace costs. Additionally, or alternatively, an air cushion may be left under the borehole cover. Removal of the manifold allows for removal of machinery from the borehole. Dedicated pumping equipment would facilitate installation, inspection, and maintenance without the need for confined space operations. A hydraulically actuated piston attached to the bottom of the reversible pump-turbine may be used to raise and lower it. A spacer between the piston and the machine may be used to allow the machine to be raised and completely clear of the borehole.

[0008] Variable speed operation is facilitated by the availability of power control electronics developed for the wind industry. As in the case of wind turbine power converters, full power converters may be used in conjunction with permanent magnet motor-generators, and partial power converters may be used in conjunction with (generally larger) doubly-fed induction generators.

[0009] The borehole in which the reversible pump-turbine is installed may include a supply for delivery of pressurized water to the bottom of the shaft through a conduit separate from the main borehole for hydraulically lifting equipment for maintenance and repair and controllably lowering the equipment to an operating position. The power connection is preferably configured to automatically engage when the machine is lowered and automatically disengage when the machine is raised. Such connectors may use conventional "wet mating" marine electrical connector technology, or may use a combination of compressed gas, insulating oil, and an inflatable seal to establish a robust electrical connection that is isolated from ground potential, for example.

[0010] The borehole in which the equipment is located may terminate at the upper portal, the lower portal, or any convenient intermediate location. For installation in conjunction with an existing pipeline, the vertical shaft may be located according to the desired pressure profile resulting from operations, load rejection, and other considerations. A shaft cover may incorporate a pressure relief valve and may be used to cover the pressure relief shaft containing air.

[0011] Multiple machines may be mounted in a single shaft, for example on a common bulkhead. A reversible pump-turbine according to the present invention may be used in conjunction with a Pelton turbine, for example, to facilitate power generation at low power levels when required. A reversible pump-turbine may also be used in conjunction with an off-season water reservoir whose primary purpose is to raise water up to the reservoir during periods of high flow and recover energy while returning the stored water when it is required downstream.

[0012] According to some embodiments of the present invention, a gas pressure balanced pressure relief valve may be used to limit excess pressure from water hammer.

[0013] A flexure with an actuatable seal may be used to connect the draft tube to the tailrace during operation. An inflatable seal may be used to seal the flexure in its operating position while allowing it to move freely during lifting and lowering operations. Inflatable seals or supports may also be used to secure the machine in place during operation and release to allow it to be lifted for maintenance.

[0014] According to a further aspect of the present invention, a reversible pump-turbine runner or pump impeller is provided that imparts an upward velocity component to the flow. This upward velocity component allows the flow to proceed directly upward through a diffuser, or a combination of guide vanes and diffusers in the case of a reversible pump-turbine, or directly to the diffuser (stator) stage in the case of a multi-stage pump, while maximizing the ratio of the impeller tip diameter to the maximum channel diameter. In the present case, this ratio may be 1.00. This maximizes the head per stage, allowing greater head to be achieved using a single-stage machine. Figures 19a, 19b, and 19c illustrate the flow in the meridian plane and the X-shaped appearance of the impeller blades when viewed toward the aft end. The present invention provides, for example, the following. (Item 1) 1. A water pumping system comprising an upper water storage tank, a lower water storage tank, and a reversible pump-turbine connected to the upper water storage tank by a headrace conduit and connected to the lower water storage tank with a discharge conduit, wherein the pump-turbine is positioned in a vertical shaft at a depth below the surface of the lower water storage tank, and wherein the pump-turbine is axially removable from the vertical shaft. (Item 2) Item 1 , the system comprising: a pump-turbine; (Item 3) Item 1. The system of item 1, wherein the headrace conduit and the discharge conduit are coaxially positioned within the vertical shaft above the pump-turbine. (Item 4) Item 10. The system of item 1, further comprising a motor-generator operably connected to the pump-turbine. (Item 5) Item 5. The system of item 4, wherein the motor-generator is positioned below the pump-turbine. (Item 6) Item 5. The system of item 4, wherein the motor-generator is above the pump-generator and operably connected thereto using a vertical drive shaft. (Item 7) Item 4. The system of item 3, wherein the coaxial conduit comprises an inner conduit and an outer conduit, and further comprises a removable manifold for directing water in the inner conduit to the lower water storage tank and for directing water from the upper water storage tank to the water conduit. (Item 8) Item 8. The system of item 7, wherein the manifold further comprises a pneumatically controlled pressure relief valve to reduce surge pressure in the water conduit. (Item 9) Item 10. The system of claim 1, further comprising a hoist piston positioned below the pump-turbine for selectively raising and lowering the pump-turbine within the vertical shaft. (Item 10) 1. A water pumping system comprising an upper water storage tank, a lower water storage tank, and a reversible pump-turbine connected to the upper water storage tank by a headrace conduit and connected to the lower water storage tank with a discharge conduit, wherein the pump-turbine is positioned within a vertical shaft at a depth below the surface of the lower water storage tank, the pump-turbine is axially removable from the vertical shaft, and the conduit is positioned coaxially with the vertical shaft. (Item 11) 1. A reversible pump-turbine located within a vertical shaft, said reversible pump-turbine being removable from said vertical shaft. (Item 12) Item 12. The apparatus of item 11, further comprising an underwater motor-generator. (Item 13) Item 13. The apparatus of item 12, wherein the motor-generator is located directly below one or more pump-turbine stages. (Item 14) Item 12. The apparatus of item 11, further comprising a removable manifold secured to the top of the shaft during operation. (Item 15) Item 15. The apparatus of item 14, wherein the removable manifold includes a pressure relief valve to relieve excess draw pressure to the discharge conduit. (Item 16) Item 16. The apparatus of item 15, wherein the pressure relief valve comprises an elastic diaphragm held by controlled gas pressure against one or more orifices containing the draw pressure. (Item 17) Item 12. The apparatus of item 11, wherein the motor-generator is located above a water intake that connects the water intake to the vertical shaft. (Item 18) Item 12. The apparatus of item 11, wherein the pump-turbine comprises multiple stages. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram of a conventional (prior art) water pumping installation. [Figure 2a] 2a and 2b are cross-sectional elevation views of a conventional pump-turbine. [Figure 2b] 2a and 2b are cross-sectional elevation views of a conventional pump-turbine. [Figure 3a] FIG. 3a is an elevational view of the water pumping facility of FIG. 3a shown with the pump-turbine assembly partially removed. [Figure 3b] With reference to Figures 3a and 3b, a reversible pump-turbine installation according to the present invention is shown. [Figure 4a] 4a and 4b are cross-sectional elevation views of a pressure relief valve configured for use with the present invention. [Figure 4b] 4a and 4b are cross-sectional elevation views of a pressure relief valve configured for use with the present invention. [Figure 5a]5a-c are cross-sectional elevation views of a reversible pump-turbine according to the present invention. [Figure 5b] 5a-c are cross-sectional elevation views of a reversible pump-turbine according to the present invention. [Figure 5c] 5a-c are cross-sectional elevation views of a reversible pump-turbine according to the present invention. [Figure 6] FIG. 6 is a cross-sectional rendering of a reversible pump-turbine and associated water pumping equipment in accordance with the present invention. [Figure 7] FIG. 7 is a cross-sectional view of a bent connection to a tailrace tunnel with an inflatable seal to secure and seal it in accordance with the present invention. [Figure 8] FIG. 8 is a cross-sectional elevation view of a pump-turbine installation in a vertical borehole adjacent to a headworks according to the present invention. [Figure 9] FIG. 9 is a cross-sectional elevation view of a pump-turbine installation in a vertical borehole in juxtaposition with a tailrace portal according to the present invention. [Figure 10] FIG. 10 is a cross-sectional elevation view of a pump-turbine installation in a vertical borehole located between a headworks and a tailrace portal in accordance with the present invention. [Figure 11] FIG. 11 is a cross-sectional elevation view of a pump-turbine installation in a vertical borehole located in conjunction with an underground pressurized water storage cavity that serves as an "upper" reservoir. [Figure 12] FIG. 12 is a schematic diagram of a pump according to the invention, typically associated with an underground air / water accumulator and a gas turbine. [Figure 13] FIG. 13 is a schematic diagram of a pump according to the present invention in association with a typically underground air / water accumulator and gas turbine, where air can be compressed near isothermally with the aid of water spray cooling. [Figure 14] 14 illustrates a tailrace connection flexure according to the present invention incorporating an inflatable seal (63) that also serves as an adjustable pressure relief element. The inflatable seal (63) features flow isolation control fins 51 to reduce vibration during operation. [Figure 15]FIG. 15 illustrates a water pumping system installation according to the present invention, including a tailrace connection bend. [Figure 16] FIG. 16 illustrates a water pumping system installation according to the present invention including a tailrace connection bend and a headrace that enters the borehole at a higher elevation than the tailrace tunnel. [Figure 17] FIG. 17 illustrates a water pumping system installation according to the present invention, including a tailrace connection bend. [Figure 18] FIG. 18 illustrates a water pumping system installation according to the present invention, including a tailrace connection bend. [Figure 19a] 19a and 19b are meridional cross-sections of a multi-stage pump impeller according to the present invention. [Figure 19b] 19a and 19b are meridional cross-sections of a multi-stage pump impeller according to the present invention. [Figure 20] FIG. 20 is a plan schematic diagram of three pump-turbines installed in association with a single headrace and single tailrace tunnel. [Figure 21] 21-23, various pressure relief valve configurations are shown. [Figure 22a] Figure 22a is a pump-turbine installation including a pressure relief valve. [Figure 22b] FIG. 22b is a schematic diagram of a torque key positioned at the bottom of the borehole for the purpose of preventing unintentional rotation of the pump-turbine. [Figure 23] FIG. 23 is a pressure relief valve according to the present invention. [Figure 24a] 24a and 24b are pressure relief valves according to the present invention shown closed and open, respectively. [Figure 24b] 24a and 24b are pressure relief valves according to the present invention shown closed and open, respectively. [Figure 25a] 25a and 25b are pressure relief valves according to the present invention shown closed and open, respectively. [Figure 25b]25a and 25b are pressure relief valves according to the present invention shown closed and open, respectively. [Figure 26a] 26a and 26b are pressure relief valves according to the present invention shown closed and open, respectively. [Figure 26b] 26a and 26b are pressure relief valves according to the present invention shown closed and open, respectively. [Figure 27] Figures 27a and 27b show the installation of multiple pump-turbines / motor-generators in a single borehole. [Figure 28] FIG. 28 shows diagrammatically one type of pump-turbine of the present invention. [Figure 29] FIG. 29 shows another version of the pump-turbine of the present invention. [Figure 30] FIG. 30 shows another version of the pump-turbine of the present invention which incorporates a cylindrical gate rather than a wicket-type gate. [Figure 31] Figures 31-37 show various installation alternatives. [Figure 32] Figures 31-37 show various installation alternatives. [Figure 33] Figures 31-37 show various installation alternatives. [Figure 34] Figures 31-37 show various installation alternatives. [Figure 35] Figures 31-37 show various installation alternatives. [Figure 36] Figures 31-37 show various installation alternatives. [Figure 37] Figures 31-37 show various installation alternatives. [Figure 38] 38-43 show various embodiments of a reversible pump-turbine. [Figure 39] 38-43 show various embodiments of a reversible pump-turbine. [Figure 40] 38-43 show various embodiments of a reversible pump-turbine. [Figure 41] 38-43 show various embodiments of a reversible pump-turbine. [Figure 42a] 38-43 show various embodiments of a reversible pump-turbine. [Figure 42b] 38-43 show various embodiments of a reversible pump-turbine. [Figure 43] 38-43 show various embodiments of a reversible pump-turbine. [Figure 44a] Figures 44a-b show the flow inverter section. [Figure 44b] Figures 44a-b show the flow inverter section. [Figure 45a] (Not specified) [Figure 45b] (Not specified) [Figure 46] (Not specified) DETAILED DESCRIPTION OF THE INVENTION

[0016] Figure 1a, 2a , and 2b , a conventional pumping plant with a reversible pump-turbine is shown. In such a conventional installation, there are several particularly expensive features. These include: 1) Pressure control shafts, typically required to mitigate water hammer that can result from load shedding. 2) Underground power plants below tailwater level. Such plants are expensive to build and are at risk of flooding due to human error or component failure. Flooding of underground power plants is a hazard to the facility and its operators. 3) The headrace and tailrace conduits must be routed at the same low elevation as the power plant itself, at great expense.

[0017] Figure 2 (Not specified)FIG. 3 is a schematic diagram of a pumping installation according to the present invention. FIG. 3 is a cross-sectional view through a meridian plane of a prior art multi-stage pump. Referring to FIGS. 3a and 3b, a reversible pump-turbine installation according to the present invention is shown. An underground powerhouse is not 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 elevation of three units below the discharge. The elevation must be sufficiently low so that the plant cavitation number (plant sigma) exceeds the critical cavitation number (critical sigma), which is defined as the ratio of the absolute pressure on the low-pressure side of the runner divided by the water vapor pressure at the water temperature. Shaft 16 connects submersible motor-generator 8 to pump-turbine stages 9, 10, 11, and 12. A vertical discharge conduit 5 connects diffuser 14 above the entry point of conduit 2. Pressure relief valve 7 is preferably mounted on removable manifold 6. Removable manifold 6 is bolted to foundation 13 and connects to tailrace conduit 3 at flange 15a. Tailrace conduit 3 leads to a lower reservoir, not shown. Note that the number of stages can be adjusted according to head, elevation setting, velocity, laying rate, and other factors. Headrace 2 connects to upper reservoir 70. Tailrace conduit 3 connects to lower reservoir 71. Water flows through outer annulus 17 of borehole 4 toward upper reservoir 70 as a pump and toward pump turbine 43.

[0018] It should be noted that the removable portions may be further divided into conveniently separable subassemblies 6, 7, 14, and 5. For example, the manifold 6 may be lifted first, the vertical portion of the tailrace conduit 5 may then be lifted, and the pump-turbine stages 9, 10, 11, and 12 may be lifted last along with the motor-generator 8. In the case of the upper motor-generator, the rotor, shaft, and remainder of the assembly may be lifted last, while the stator is left in place.

[0019] 4a and 4b, cross-sectional views of a pressure relief valve suitable for use with the present invention are shown in its open and closed positions, respectively. Diffuser 14 is connected to ribs 25. Ribs 25, rings 23, and rings 24 together support bladder 18 radially on its inner diameter surface when its inflation pressure exceeds the pressure in shaft 17. Inflatable bladder 18 is supported from below by flange 26 and on its outer diameter by enclosure 7. The air pressure in bladder 18 can be precisely adjusted only to stop leakage (at discharge pressure) from shaft 17 to manifold 6.

[0020] Referring to Figures 5a and 5b, cross-sectional elevation views of a pump-turbine according to the present invention are shown. The runner 27 is designed around a toroidal flow path in which the water reverses direction approximately 180° in the meridional plane. A wicket gate 28 constitutes an axial flow distributor. A turbine diffuser 29 recovers turbine runner exit energy. Fixed vanes 30 provide mechanical support for the distributor hub 31, turbine diffuser 29, and wicket gate servo system 32. A generator 33 is preferably located below the turbine. A hoist piston 34 can be used to raise and lower the entire pump-turbine assembly, including the connected draft tube section, pressure relief valve, and bend, using water pressure. The hoist piston 34 incorporates upper and lower sealing rings 35 and 36 and can pass across the tailrace connection while maintaining a seal.

[0021] A hollow shaft 72 may be used as the evaporator for the heat pipe with runner 27 acting as a condenser. When the machine is lowered, an electrical connector 73 engages an electrical outlet assembly 74. Bias rings 75 and 76 provide the torque to operate the wicket gate 28.

[0022] The borehole 4 is associated with a rock face 77 , grout 78 , and a steel liner 79 .

[0023] The shaft seal assembly 80 keeps the generator enclosure dry.

[0024] Referring to Figure 6, a piston assembly 34 supports the generator 33 and pump turbine 37 during ascent and descent. A valve 38 can be used to shut off water from the headrace 39. A tailrace conduit 40 connects to the tailrace. A cover assembly 41 is removable.

[0025] Referring to Figure 6, a valve 42 may be used to fill the vertical shaft 4 during hydraulic raising and lowering of the pump-turbine motor-generator assembly 43 with attached pipe, bend, and pressure relief assembly 44, and a lower portal 45 serves to start the TBM during the construction phase and serves as a pumping inlet station. A headworks 47 serves as an upper portal during construction and as an inspection platform during maintenance. A crane 48 may be used to disassemble the draft tube section, bend assembly, and pressure relief valve from the pump-turbine for maintenance.

[0026] Referring to Figure 7, flexure assembly 49 is shown. Inflatable seal 50 seals the upper end. Inflatable seal 51 closes the lower end. Flexure 52 directs flow into the tailrace conduit. Spool 53 travels with the pump-turbine during maintenance movements.

[0027] Referring to Figure 8, a laying is shown in which the machine shaft 54 ​​is located below the headworks 55.

[0028] Referring to FIG. 9, a machinery shaft 54 ​​is located below the tailrace portal 56 .

[0029] Referring to FIG. 10, a machine shaft 54 ​​is located between a headworks 55 and a spillway portal 56 .

[0030] Referring to FIG. 11, a mechanical shaft 54 ​​provides connections to a pressurized reservoir 58 and a tailrace tunnel 59 .

[0031] 12, a pressurized water reservoir 58 is shown along with a pressurized air column 59. A pump or pump / turbine 60 may be in accordance with the present invention or may be conventional. Air 59 may be delivered to a gas turbine generator set 61.

[0032] Referring to FIG. 13, spray cooling of the air being compressed may be used to provide isothermal air compression.

[0033] Figures 6, 7, 16, and 17 depict one of many possible construction sequences.

[0034] Referring to Figure 17, another embodiment is shown in which the inflatable seal 63 can also act as a pressure relief valve.

[0035] 18, a combined seal and PRV 63 is shown positioned within the machine shaft 54, along with the bend 52 and tailrace conduit 40. The machine shaft liner 64 is shown.

[0036] Referring to Figure 17, another embodiment is shown in which the inflatable seal 63 can also act as a pressure relief valve.

[0037] Referring to FIG. 18, another embodiment is shown with vanes 65 within bends 52.

[0038] Referring to Figures 19a and 19b, a runner for a pump or reversible pump-turbine is shown, where the flow is directed along a smooth sinusoidal path in the meridional plane. The blades impart circumferential and meridional acceleration vectors, directing the water through the water passage. The blade sequence may be normal to the vector sum. Larger impellers are more efficient and provide higher head per stage. Impellers may best be fabricated by three-dimensional printing. Figure 19c is an end view of the impeller of Figure 19b, looking into the discharge edge.

[0039] 21-23, various pressure relief valve configurations are shown.

[0040] Referring to Figure 24, an intermediate vane is used.

[0041] Referring to FIG. 27, multiple pump-turbines are shown sharing a common headrace 2 and tailrace conduit 3 .

[0042] 27A and 27b, multiple submersible pump-turbines 62a-62f are shown co-located within the same machine shaft 54. As shown in FIG.

[0043] 28 to 30 show a pump-turbine configured for installation on a bulkhead in a common machine shaft.

[0044] Referring to Figure 31, a medium / high voltage permanent magnet motor / generator 95 and a battery storage array 98 are connected to a power grid 90 via a single cascaded multilevel power converter. The power converter comprises a phase-shifted input transformer 92, power cells 93 incorporating a regenerative front end, an isolated DC bus 95, and a load-side inverter 94. The DC bus of each power cell is connected to a battery bank 98 via a disconnect switch 97.

[0045] The voltage of the individual DC buses 96 is actively managed during operation to charge or discharge the battery banks 98 independently of the power consumed or generated by the motor / generators 95 .

[0046] Referring to Figure 32, a low-voltage permanent magnet motor / generator 95 and a battery storage array 98 are connected to a power grid 90 through a single two-level power converter. The power converter comprises an active front end 93 with a line-side reactor, an intermediate DC bus 96, and a motor-side two-level inverter 94. The power converter is connected to the power grid through a disconnector 100 and a step-up transformer 99. The power converter DC bus 96 is attached to the battery array 98 through a disconnect switch 97. The voltage of the DC bus 96 is actively managed during operation to charge or discharge the battery array 98 independently of the power consumption or generation by the motor / generator 95.

[0047] Referring to Figure 33, a permanent magnet motor / generator 95 and a battery storage array 98 are connected to a power grid 90 using parallel and independent power converters. The converters may be connected using individual disconnectors 91 that incorporate protection features. The motor / generator 95 is connected using a regenerative AC / AC power converter 102. The battery array 98 is connected to a grid-tie inverter 101 through a DC bus disconnector 97. A step-up transformer 99 increases the output of the inverter 101 to the grid voltage. Optionally, a disconnector 100 is installed between the transformer 99 and the battery inverter 101.

[0048] Referring to Figure 34, a medium / high voltage doubly fed induction machine 103 and battery storage array 98 are connected to the utility grid 90. The rotor winding of the generator is connected to a cascaded multilevel AC / AC drive with battery storage connected as described in Figure 31. The stator winding of the generator is connected to the utility grid through a disconnector 104.

[0049] Referring to Figure 35, a medium / high voltage doubly fed induction machine 103 and battery storage array 98 are connected to the utility grid 90. The rotor winding of the generator is connected to a low voltage two level AC / AC drive with the battery storage connected as described in Figure 32. The stator winding of the generator is connected to the utility grid through a disconnector 104.

[0050] Referring to Figure 36, a medium / high voltage doubly fed induction machine 103 and battery storage array 98 are connected to the utility grid 90. The generator rotor winding is connected to a regenerative AC / AC drive 102. The generator rotor winding is connected to the utility grid through a disconnector 104. The battery storage array is connected to a separate and independent DC / AC inverter 101 as illustrated in Figure 33.

[0051] Referring to FIG. 37, multiple medium / high voltage permanent magnet motor / generators 95 are connected to the utility grid 90 in an arrangement that allows direct synchronous connection of either one, using a direct online contactor 105 in conjunction with forward / reverse selection contactors 106 / 107, which are interlocked to prevent simultaneous closure. A regenerative power converter 102 can be used to allow the generator to reach synchronous speed in either pumping or generating mode, or to operate at variable speed rather than synchronous speed. A phase-shifted input transformer 92 connects the active front end of the converter 102 to the utility grid through a disconnector 91. A matrix of disconnectors 108 allows any of the generators to be operated or started using any of the power converters.

[0052] As can be readily understood from the foregoing, the basic concepts of the present invention can be embodied in a variety of ways, involving both water control and actuator techniques and devices for achieving the appropriate water control or actuation. In this application, water control techniques are disclosed as part of the results shown to be achieved by the various devices described, as well as steps inherent in their use. They are simply the natural result of using the devices as intended and described. Additionally, while several devices are disclosed, it should be understood that these not only accomplish certain methods but can also be varied in several respects. Importantly, with regard to all of the foregoing, all of these aspects should be understood to be encompassed by the present disclosure.

[0053] The discussion contained herein is intended to serve as a basic description. The reader should recognize that the specific discussion may not explicitly describe all possible embodiments, and that many alternatives are implicit. It may also not fully describe the general nature of the invention and may not explicitly indicate how each feature or element may actually represent a broader function or a wide variety of alternative or equivalent elements. Again, these are implicitly included in this disclosure. When the invention is described in device-oriented terms, each element of the device implicitly performs a function. Not only may apparatus claims be included for the described device, but method or process claims may also be included to address the invention and the function performed by each element. Neither the description nor the terminology is intended to limit the scope of the claims that may be included in this patent application.

[0054] It should also be understood that various modifications may be made without departing from the essence of the invention. Such modifications are also implicitly included in the description. They still fall within the scope of the invention. The broad disclosure, encompassing both the explicit embodiments shown and the wide variety of implicit alternative embodiments, and the broad method or process and equivalents, are encompassed by this disclosure and may be relied upon in the claims for this patent application. It should be understood that such language may vary and that broad claims may be pursued in this application. This patent application seeks consideration of as broad a claim basis as is deemed within the applicant's rights, and will be designed to result in a patent that covers multiple aspects of the invention, both independently and as an overall system.

[0055] Furthermore, each of the various elements of the invention and claims may also be achieved in various ways. The present disclosure should be understood to encompass each such variation, whether it be a variation of any apparatus embodiment, method, or process embodiment, or even simply a variation of any of these elements. In particular, as the present disclosure relates to elements of the invention, it should be understood that the terms for each element may be expressed in equivalent apparatus terms or method terms, even if only the function or result is identical. Such equivalent, broader, or even more general terms should be considered to be encompassed in the description of each element or action. Such terms may be substituted where desired to make explicit the implicitly broad claims to which the present invention is entitled. As an example only, it should be understood that any action may be expressed as a means for taking any action or as an element that causes that action. Similarly, each physical element disclosed should be understood to encompass a disclosure of the action that the physical element facilitates. With respect to this last aspect, by way of example only, disclosure of a "means for actuating" or "actuator" should be understood to encompass disclosure of the act of "actuating," whether or not explicitly discussed, and conversely, if there is in fact a disclosure of the act of "actuating," such disclosure should be understood to encompass disclosure of an "actuator" and also a "means for actuating." Such variations and alternative terms are to be understood as expressly included in the description.

[0056] Any act of law, statute, ordinance, or regulation referred to in this patent application, or any patent, published document, or other reference referred to in this patent application, is hereby incorporated by reference. Additionally, it is understood that for each term used, common dictionary definitions, such as those contained in The Random House Webster's Unabridged Dictionary (2nd Edition), which is incorporated herein by reference, should be understood to be incorporated for each term, all definitions, alternative terms, and synonyms, unless its use in this application is inconsistent with such interpretation. Finally, all references listed in the list of references incorporated by reference pursuant to this patent application, or other statements of information filed in this application, are attached hereto and incorporated by reference; however, with respect to each of the above, to the extent that such information or statements incorporated by reference may be deemed inconsistent with the patent of this / these inventions, such statements shall not be expressly deemed to have been made by the applicant. [Table 1] [Table 2-1] [Table 2-2] [Table 3] [Table 4-1] [Table 4-2]

Claims

1. 1. A device for imparting work to a fluid and changing the direction of said fluid, comprising: an impeller having an impeller inlet through which the fluid flows as an impeller inlet in a first direction within a meridian plane defined by the device; blades of the impeller downstream of the impeller inlet, the blades defining an impeller axis of rotation and configured to contact and turn the impeller inflow along a toroidal flow path to produce an impeller discharge having both axial and tangential velocity components; the axial velocity component is at substantially 180 degrees in the meridian plane relative to the first direction of impeller inflow; a diffuser disposed about a diffuser axis aligned with the impeller axis of rotation; the diffuser has a diffuser inlet through which the diffuser inflow flows and which has a diffuser inlet annular radial dimension, and a diffuser outlet through which the diffuser outflow flows and which has a diffuser outlet annular radial dimension, the diffuser outlet annular radial dimension being greater than the diffuser inlet annular radial dimension; the diffuser further includes curved diffuser vanes provided as part of the diffuser to redirect the impeller discharge to reduce the tangential velocity component. Device.

2. 10. The apparatus of claim 1, wherein the diffuser has an outer diffuser radius and the impeller has an outer impeller radius, the outer diffuser radius being no greater than the outer impeller radius.

3. The apparatus of claim 1 , wherein the diffuser is disposed about the impeller inlet.

4. The apparatus of claim 1 , wherein the impeller inlet comprises a pump inlet nozzle.

5. The apparatus of claim 4 , wherein the pump inlet nozzle comprises a draft tube.

6. The apparatus of claim 4 , wherein the pump inlet nozzle is coaxially disposed within the diffuser.

7. The apparatus of claim 1 , wherein the apparatus is selected from the group consisting of a blower, a pump, and a compressor.

8. The apparatus of claim 1 , wherein the apparatus is operable as a turbine.

9. The apparatus of claim 1 , wherein the apparatus is a turbine and a pump.

10. The apparatus of claim 1 , wherein the impeller comprises a toroidal impeller.

11. The apparatus of claim 1 further comprising a flow inverter connecting the diffuser outlet to a pump outlet pipe.

12. The device of claim 1 , wherein the diffuser comprises a plurality of vanes of similar length.

13. 10. The apparatus of claim 1, wherein the diffuser comprises a plurality of vanes, the length of at least one of the vanes being different from the length of at least one other vane.

14. The apparatus of claim 1 further comprising a motor-generator, a headrace connection, and a tailrace connection.

15. 15. The apparatus of claim 14, wherein the motor-generator is disposed at a height higher than the impeller, a height higher than the headrace connection, and a height higher than the tailrace connection.

16. 10. The apparatus of claim 1, further comprising a pitless adapter sealed to the well casing with a pressure seal.

17. 1. A device for imparting work to a fluid and changing the direction of said fluid, comprising: an impeller having an impeller inlet through which the fluid flows as an impeller inlet in a first direction in a meridional plane through the device; blades of the impeller downstream of the impeller inlet, the blades defining an impeller axis of rotation and configured to contact and turn the impeller inflow along a toroidal flow path to produce an impeller discharge having both axial and tangential velocity components; the axial velocity component is at substantially 180 degrees in the meridian plane relative to the first direction of impeller inflow; a diffuser disposed about a diffuser axis aligned with the impeller axis of rotation; the diffuser has a diffuser inlet through which the diffuser inflow flows and which has a diffuser inlet annular radial dimension, and a diffuser outlet through which the diffuser outflow flows and which has a diffuser outlet annular radial dimension, the diffuser outlet annular radial dimension being greater than the diffuser inlet annular radial dimension; Device.

18. 18. The apparatus of claim 17, wherein the diffuser has an outer diffuser radius and the impeller has an outer impeller radius, the outer diffuser radius being no greater than the outer impeller radius.

19. 20. The apparatus of claim 17, wherein the diffuser further comprises curved diffuser vanes configured to redirect the impeller discharge to reduce the tangential velocity component.

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