WO2016118266A1 - Variable performance electric generator - Google Patents
Variable performance electric generator Download PDFInfo
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- WO2016118266A1 WO2016118266A1 PCT/US2015/066554 US2015066554W WO2016118266A1 WO 2016118266 A1 WO2016118266 A1 WO 2016118266A1 US 2015066554 W US2015066554 W US 2015066554W WO 2016118266 A1 WO2016118266 A1 WO 2016118266A1
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- Prior art keywords
- generator
- pressure
- rotor
- gas
- core
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- 239000000112 cooling gas Substances 0.000 claims abstract description 40
- 239000007789 gas Substances 0.000 claims abstract description 40
- 238000001816 cooling Methods 0.000 claims abstract description 29
- 238000004804 winding Methods 0.000 claims abstract description 15
- 239000002826 coolant Substances 0.000 claims abstract description 12
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 14
- 239000001257 hydrogen Substances 0.000 description 14
- 229910052739 hydrogen Inorganic materials 0.000 description 14
- 239000002360 explosive Substances 0.000 description 12
- 238000012546 transfer Methods 0.000 description 8
- 238000004880 explosion Methods 0.000 description 6
- 239000004020 conductor Substances 0.000 description 5
- 238000013461 design Methods 0.000 description 5
- 239000007788 liquid Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000010248 power generation Methods 0.000 description 3
- 230000008646 thermal stress Effects 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 239000004744 fabric Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 206010063493 Premature ageing Diseases 0.000 description 1
- 208000032038 Premature aging Diseases 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000012774 insulation material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000011017 operating method Methods 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K9/00—Arrangements for cooling or ventilating
- H02K9/10—Arrangements for cooling or ventilating by gaseous cooling medium flowing in closed circuit, a part of which is external to the machine casing
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K9/00—Arrangements for cooling or ventilating
- H02K9/08—Arrangements for cooling or ventilating by gaseous cooling medium circulating wholly within the machine casing
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K5/00—Casings; Enclosures; Supports
- H02K5/02—Casings or enclosures characterised by the material thereof
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K5/00—Casings; Enclosures; Supports
- H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
- H02K5/12—Casings or enclosures characterised by the shape, form or construction thereof specially adapted for operating in liquid or gas
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K9/00—Arrangements for cooling or ventilating
- H02K9/19—Arrangements for cooling or ventilating for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil
- H02K9/197—Arrangements for cooling or ventilating for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil in which the rotor or stator space is fluid-tight, e.g. to provide for different cooling media for rotor and stator
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P8/00—Arrangements for controlling dynamo-electric motors rotating step by step
- H02P8/36—Protection against faults, e.g. against overheating or step-out; Indicating faults
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K2213/00—Specific aspects, not otherwise provided for and not covered by codes H02K2201/00 - H02K2211/00
- H02K2213/09—Machines characterised by the presence of elements which are subject to variation, e.g. adjustable bearings, reconfigurable windings, variable pitch ventilators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K3/00—Details of windings
- H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
- H02K3/24—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors with channels or ducts for cooling medium between the conductors
Definitions
- Dynamoelectric high-voltage machines and/or high-voltage systems such as electrical generators in power plants, represent a substantial capital investment. Furthermore, it is desirable to avoid over-sizing in terms of the performance capability of the generator.
- Another aspect includes the output parameter of the generator is selected from the group consisting of terminal voltage, phase current demand, power factor and combinations thereof.
- metallic thin plate material utilized for the low pressure frame or pressure boundary member 4 may be between approximately 5mm and 15mm thick and film or fabric may be between approximately 1 mm and 5mm thick.
- Typical hydrogen cooled generators have much thicker steel walled frames due to the fact that the hydrogen cooling gas pressure is typically 3 to 5 bar gauge pressure, as well as the frame must be strong enough to contain the internal pressure due to an explosion of the hydrogen cooling gas. In order for the typical hydrogen cooled generator frame to contain the pressure for an internal explosion of hydrogen cooling gas, the frame walls are typically approximately 19 mm to 51 mm thick.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Motor Or Generator Cooling System (AREA)
Abstract
A variable pressure electric generator, including a gas cooled rotor arranged along a centerline of the generator; a gas cooled core arranged coaxially and surrounding the rotor; a plurality of coils arranged within the core; a stator frame arranged to fixedly support the core and rotationally support the rotor; a gas cooling system that circulates a cooling gas within the generator; a pressurizing system that operatively pressurizes the cooling medium to a maximum pressure of 2 bar relative to atmospheric pressure, wherein the pressurizing system continuously determines the cooling medium pressure based upon operational requirements; and a low pressure frame that surrounds a plurality of the rotor and an entirety of the core and stator windings, the frame configured to operatively contain an internal pressure of 2 bar relative to atmospheric pressure.
Description
VARIABLE PERFORMANCE ELECTRIC GENERATOR
CLAIM OF PRIORITY AND CROSS REFFERENCE TO RELATED APPLICATIONS
The instant application claims benefit and priority to US provisional application 62/105,798 filed on January 21 , 2015 and is incorporated herein in its entirety. Furthermore, this application is related to application's 14/938,313;
14/938,342; 14/938,364 and 14/938,382 (attorney docket #'s 2015P00589US01 , 2015P20070US, 2015P20071 US and 2015P20072US) filed concurrently.
FIELD OF THE INVENTION
The present invention relates to high voltage power generation equipment and, more particularly, to a variable performance electric generator.
BACKGROUND OF THE INVENTION
Dynamoelectric high-voltage machines and/or high-voltage systems, such as electrical generators in power plants, represent a substantial capital investment. Furthermore, it is desirable to avoid over-sizing in terms of the performance capability of the generator.
Due to the serious technical issues presented to the power generation industry due to part-load and varying-load operation, there is a significant need for a simple, low cost generator with a variable maximum efficiency/variable maximum out-put as well as a generator with reduced winding insulation thermal stresses and greater winding life.
SUMMARY OF THE INVENTION
One aspect is a variable pressure electric generator, including a gas cooled rotor arranged along a centerline of the generator; a gas cooled core arranged coaxially and surrounding the rotor; a plurality of coils arranged within the core; a stator frame arranged to fixedly support the core and rotationally support the rotor; a gas cooling system that circulates a cooling gas within the generator; a pressurizing system that operatively pressurizes the cooling medium to a maximum pressure of 2 bar relative to atmospheric pressure, wherein the pressurizing system continuously
determines the cooling medium pressure based upon operational requirements; and a low pressure frame that surrounds a plurality of the rotor and an entirety of the core and stator windings, the frame configured to operatively contain an internal pressure of 2 bar relative to atmospheric pressure.
Another aspect includes the pressurizing system further comprising a controller and a pressurizing unit.
Another aspect includes the controller configured to receive a sensor signal representative of an output parameter of the generator.
Another aspect includes the controller configured to determine an optimum operating pressure based on a predetermined operational scheme.
Another aspect includes the output parameter of the generator is a control room signal.
Another aspect includes the output parameter of the generator is selected from the group consisting of terminal voltage, phase current demand, power factor and combinations thereof.
Another aspect is a variable efficiency electric generator, including a gas cooled rotor arranged along a centerline of the generator; a gas cooled core arranged coaxially and surrounding the rotor; a plurality of coils arranged within the core; a stator frame arranged to fixedly support the core and rotationally support the rotor; a gas cooling system that circulates a cooling gas within the generator; a variable pressure control system that variably a regulates a pressure of the cooling medium between zero (0) bar and two (2) bar relative to atmospheric pressure in accordance with a predetermined operational scheme; and a low pressure frame that surrounds a plurality of the rotor and an entirety of the core and stator windings, the frame configured to operatively contain an internal pressure of two (2) bar relative to atmospheric pressure.
Another aspect includes the variable pressure control system further comprises a controller and a pressurizing unit.
Another aspect includes the controller is configured to receive a sensor signal representative of an output parameter of the generator.
Another aspect includes the controller is further configured to determine an optimum operating pressure based on the predetermined operational scheme.
Another aspect includes the maximum operational efficiency of the generator is at a part-load condition.
Another aspect includes the maximum operational efficiency of the generator is between 20% to 80% of maximum power output.
Another aspect includes the maximum operational efficiency of the generator is between 50% to 70% of maximum power output.
Another aspect includes the operative pressure of the cooling gas is a function of an output parameter of the generator.
Another aspect includes the output parameter of the generator is a control room signal.
Another aspect includes the output parameter of the generator is selected from the group consisting of terminal voltage, phase current demand, power factor and combinations thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
While the specification concludes with claims particularly pointing out and distinctly claiming the present invention, it is believed that the present invention will be better understood from the following description in conjunction with the accompanying Drawing Figures, in which like reference numerals identify like elements, and wherein:
Fig. 1 depicts a gas cooled generator system, cooling gas pressurizing unit and associated control system;
Fig. 2 is depicts a stator core and a winding coil residing within the core;
Fig. 3 depicts an insulated coil;
Fig. 4 depicts an end view of coil showing the conductors;
Fig 5 depicts various coil thermal responses due to a step change in generator load; and
Fig 6 depicts comparison of efficiency vs. load for equivalent rated
generators.
DETAILED DESCRIPTION OF THE INVENTION
In the following detailed description of the preferred embodiment, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, and not by way of limitation of the embodiment. It is to be understood that other embodiments may be utilized and that changes may be made without departing from the spirit and scope of this disclosure.
Currently, an electrical generator is configured or sized for the required maximum power output (MVA) which represents a particular physical configuration of the generator and an associated operating efficiency and cost to manufacture. However, modern power plants now see greater variation in required power output demand from the grid and associated operating conditions. In particular, one common variation modern power plants are experiencing is the requirement to operate at part-load conditions. For example, within the United States, generators do not typically operate at full load, rated power factor conditions. Instead, these generators typically operate approximately 80% of full load and at a variety of power factors. Part-load conditions can be any operating condition less than 100% power output. However, part-load operation typically is within the range of 20%-80% of maximum power output. Additionally, part-load conditions may be more specifically 60%-80% of maximum power output.
Furthermore, the state of the art of electric generator technology represents three primary configurations for cooling the generator rotor and stator, i) air cooling for both the rotor and stator, ii) hydrogen cooling for both the rotor and stator, and iii) water cooling for the stator coils and hydrogen cooling for the rotor and stator core. Air cooled electric generators are lower cost and mechanically less complex than hydrogen cooling and/or the combination of hydrogen and water cooling.
Advances in power plant prime mover power output capability have led to a demand for generator ratings that extend beyond the current capability of low-cost, conventional air-cooled units. Conventional air-cooled designs in the industry have generally been limited to approximately 350 MVA.
Typically, for applications above 350 MVA, a pressurized hydrogen-cooled generator is required. Although hydrogen is an excellent coolant, hydrogen-cooled generators are inherently more complex, more expensive to build and more expensive to operate than air-cooled generators due to the need to (i) prevent the mixing of hydrogen and air (i.e. complicated and expensive sealing systems and operating procedures) and (ii) the need to contain a potential hydrogen explosion within the generator (a very robust pressure vessel frame capable of containing the explosion pressure).
Furthermore, with the typical gas-cooled (air or hydrogen) generator, the cooling gas circuit is designed for 100% power output of the generator. However, when operating at part-load, the generator is not producing full power but the windage losses from the cooling gas circuit remain constant. Therefore, the generator and the power plant are operating at sub-optimal efficiency.
In addition to part-load operation, another common variation modern power plants are experiencing is the requirement to change load frequently. An issue associated with varying-load operation of the generator is large variations in operating temperatures of the stator and rotor windings due to the variations in power output to match the operational load demand. The variations in operating temperatures of the windings results in excessive thermal stress cycles of the winding components and premature aging of the insulation materials due to the change from one operating state of the generator to another, see Fig 5.
Heat from traditional gas cooled generators is removed through convective heat transfer from the generator active components to the cooling gas. In the most simplistic terms, heat is primarily removed from generator components via convective heat transfer which is defined by:
Q = m*Cp*dTg. Eq. (1 ), and
Q= h*A*dTs, where h is (m, k) Eq. (2).
As can be seen by examination of Eq. (1 ) above, heat to be removed from the generator (Q) can be increased by increasing cooling gas mass flow rate (m), cooling gas specific heat (Cp), and/or the cooling gas temperature rise along the flow-path (dTg). Eq. (2) shows that Q can also be increased by increasing the heat
transfer coefficient (h) as well as the temperature differential between the
component temperature and the cooling gas (dTs). Furthermore, the heat transfer coefficient is a direct function of m and gas thermal conductivity (k). Heat transfer can also be increased by increasing the surface area (A) of the component to be cooled, but this is typically constrained by other design criteria. Increasing the cooling gas pressure from 0 to 1 bar gage effectively doubles m and therefore the cooling capacity of the gas. The dTs is typically limited by the material properties used in the construction of the generator components. However, dTs is generally maximized while meeting design requirements such as low and high cycle fatigue life and acceptable thermal stresses. The Cp and k are dependent on the selected cooling gas chemistry. Typically, Cp and k are greater for lighter gases like hydrogen or helium, and less for heavy gases such as air, molecular nitrogen or carbon dioxide. Historically, generator designs have tried to optimize heat removal through the optimal selection of Cp and k of the cooling gas along with the cooling gas density by determining a fixed operating gas pressure.
It can be observed that the largest benefit from pressurization occurs from 0 bar gauge to 1 bar gauge pressure, i.e. a doubling of cooling gas pressure results in a doubling of the heat transfer capacity of the cooling gas. Increased benefit due to higher pressurization diminishes as the cooling gas pressure increases above 1 bar gauge pressure. However, further pressurization to approximately 2 bar gauge pressure may still provide acceptable heat transfer and performance gains.
However, the drawback of increased pressurization is increased fluid pumping losses (known as windage) due to the increased density of the cooling gas.
The positive and negative impacts of cooling gas pressurization must be balanced to obtain an optimal configuration. Gas pressurization increases heat removal capacity, but also increases the heat generation through windage/friction and therefore reduces efficiency of the generator.
Referring to Fig. 1 , an embodiment provides a gas cooled generator 1. The generator 1 includes a rotor 2 arranged along a centerline 3 of the generator 1. The
generator further includes a stator core 5 arranged coaxially with the rotor 2 and at least partially surrounds the rotor 2.
As can be seen in Fig's. 2 and 3, the stator core 5 supports a plurality of electrical conducting coils 100. The plurality of coils 100 are commonly known within the power generation industry as windings 6. The coil 100 typically consist of electrical conductors 103 surrounded by electrical insulation 101 to electrically isolate the electrical conductors from the stator core 5 and other surrounding components of the generator 1. One of ordinary skill in the art of electrical generator design can readily appreciate that there are several common schemes for cooling the windings 6.
For example, as can be seen in Figs 2, 3 and 4, coil 100 can be cooled indirectly by conductive heat transfer to the stator core 5. That is, the winding 6 is not cooled directly by a cooling medium. Rather, the heat generated within the coil 100 due to operation is conducted to the stator core 5 and the stator core 5 is then cooled by a cooling medium.
In a further example, and as can be seen in Fig. 4, another means of cooling the coil 100 is direct cooling, where cooling passages 102 are formed within or adjacent to the coil 100 itself. The cooling passages 102 can be formed integrally with and as an electrical conductor 103 or the cooling passages 102 can be formed discretely from the electrical conductor 103 as a separate component.
Referring again to Fig 1 , the embodiment further provides a low pressure pressurizing unit 7 configured to vary an operating pressure of a non-explosive cooling gas 10 typically between atmospheric pressure (0 bar gauge) and 1 to 2 bar above atmospheric (1 to 2 bar gauge) as determined by control system 21. The pressurizing unit 7 may incorporate a compressor to pressurize the cooling gas, a pressure reservoir to store a large volume of compressed gas to facilitate the rapid pressurization of the generator 1 as determined by the control system 21 , and an adjusting device 8 where the adjusting device 8 may be a control valve.
Furthermore, the compressor could be a standalone device or could be represented
an extraction of compressed gas from another device like a gas turbine compressor or steam turbine.
The control system 21 continuously senses a state of the power output of the generator to the electrical grid 22. The control system 21 may sense the load on the generator 1 from typical control room signals, for example, such as terminal voltage, phase current demand, and power factor. The control system 21 then compares the sensed generator output signal 22 to the load demand of the generator 1 and determines an optimum pressure of the cooling gas 10 based on a predetermined control scheme. Once the optimum pressure of the cooling gas 10 is determined by the control system 21 in conjunction with the predetermined scheme, a control signal 23 is generated by the control system 21 and transmitted to the pressurizing unit 7. The pressurizing unit 7 then adjusts the operating pressure of the cooling gas 10 in accordance with the control signal 23. The pressure control scheme can be customized to maximize generator efficiency.
A further aspect may utilize liquid cooling of the stator coil 100 to provide additional operational flexibility, improved efficiency and reliability of the coil 100, see Fig's 4 and 5. The combination of direct liquid cooling of the stator coils 100 with low pressure non-explosive gas cooling of the stator core 5 and the rotor 2 results in greater operational flexibility and efficiency of the generator 1. Liquid cooling of the stator coils 100 eliminates the heat load from the stator coils 100 on the cooling gas 10 which thereby reduces the heat demand on the overall cooling gas system (i.e. cooling unit 9, cooling gas 10, blower 11 and pressurizing unit 7). Therefore, the losses due to the gas cooling system can be minimized.
Additionally, the control system 21 may further control the pressurizing unit 7 along with the liquid cooling of the stator coils 100 to regulate the generator component temperatures in accordance with the predetermined scheme to minimize thermally induced stresses of the various components like the stator coils 100 and rotor 2, so as to maximize the life of the low pressure non-explosive gas generator 1 in environments where load cycling is excessive, see Fig 5.
A further aspect utilizes a pressure boundary member 4 to contain the pressure of the cooling gas 10. The pressure boundary member 4 may be formed as a frame from thin plate material or as a semi-flexible pressure containment device formed from film or fabric, all of which may be made from a polymer, metallic or composite materials of sufficient construction to withstand the operating
environment of the generator, i.e. temperature, pressure, vibration and
environmental considerations. Typically, metallic thin plate material utilized for the low pressure frame or pressure boundary member 4 may be between approximately 5mm and 15mm thick and film or fabric may be between approximately 1 mm and 5mm thick. Typical hydrogen cooled generators have much thicker steel walled frames due to the fact that the hydrogen cooling gas pressure is typically 3 to 5 bar gauge pressure, as well as the frame must be strong enough to contain the internal pressure due to an explosion of the hydrogen cooling gas. In order for the typical hydrogen cooled generator frame to contain the pressure for an internal explosion of hydrogen cooling gas, the frame walls are typically approximately 19 mm to 51 mm thick. The present frame or pressure boundary 4 is intended only to withstand the relatively low pressure of 1 to 2 bar gauge pressure and due to the non-explosive nature of the cooling gas; the frame 4 does not have to contain explosion pressures. Therefore, the low pressure frame need 4 only be sized and configured to meet the operating conditions of a non-explosive cooling gas low pressure generator and not the explosion pressures resulting in a structurally thinner frame or pressure boundary member 4.
Additionally, through the benefit of low pressure gas cooling to a maximum of 1 to 2 bar gauge pressure, the entire generator can be sized much smaller than an equivalent output traditional air cooled generator. For example, the present low pressure non-explosive gas generator 1 can be smaller in physical size than present air cooled generators by 10 to 35%. Preferably, the present low pressure non- explosive gas generator 1 could be 35% smaller in physical size than a typical air cooled generator, or alternatively, the present low pressure non-explosive gas generator 1 could achieve a 50% to 60% increase in power output compared to a typical air cooled generator of the same size or physical dimensions.
Furthermore, if the power output demands of the generator exceed the power output limits of the generator 1 , the cooling gas pressure can be quickly and easily increased up to 1 bar gauge pressure and furthermore to a maximum of 2 bar gauge pressure for additional generator power output capacity. For example, by varying gas pressure between 0 and 1 bar gauge, an increase of approximately 50% of additional power output capability with no other modification required to the generator 1 , see Fig 6.
Furthermore, the cooling system of the low pressure non-explosive gas generator 1 is physically smaller than that of a typical air cooled generator due to the combination of pressurized air cooling and a water-cooled stator winding.
Therefore, the windage losses for the low pressure non-explosive gas generator 1 are greatly reduced as compared to an equivalent power output traditional air cooled generator. At power outputs less than 100% rated output, the cooling gas pressure of the low pressure non-explosive gas generator 1 can be reduced to obtain the overall efficiencies that improve at partial load, see Fig 6.
In a further aspect, the low pressure non-explosive gas generator 1 may utilize alternate gasses as the cooling medium. Such gases are listed in Table 1 below.
Table 1
Additionally, the gasses identified in Table 1 may also be mixed
combinations to provide specific performance characteristics.
While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.
Claims
1 . A variable pressure electric generator, comprising:
a gas cooled rotor arranged along a centerline of the generator;
a gas cooled core arranged coaxial ly and surrounding the rotor;
a plurality of coils arranged within the core;
a stator frame arranged to fixedly support the core and rotationally support the rotor;
a gas cooling system that circulates a cooling gas within the generator;
a pressurizing system that operatively pressurizes the cooling medium to a maximum pressure of 2 bar relative to atmospheric pressure, wherein the
pressurizing system continuously determines the cooling medium pressure based upon operational requirements; and
a low pressure frame that surrounds a plurality of the rotor and an entirety of the core and stator windings, the frame configured to operatively contain an internal pressure of 2 bar relative to atmospheric pressure.
2. The generator of claim 1 , wherein the pressurizing system further comprises a controller and a pressurizing unit.
3. The generator of claim 2, wherein the controller is configured to receive a sensor signal representative of an output parameter of the generator.
4. The generator of claim 3, wherein the controller is further configured to determine an optimum operating pressure based on a predetermined operational scheme.
5. The generator of claim 2, wherein the output parameter of the generator is a control room signal.
6. The generator of claim 6, wherein the output parameter of the generator is selected from the group consisting of terminal voltage, phase current demand, power factor and combinations thereof.
7. A variable efficiency electric generator, comprising:
a gas cooled rotor arranged along a centerline of the generator;
a gas cooled core arranged coaxial ly and surrounding the rotor;
a plurality of coils arranged within the core;
a stator frame arranged to fixedly support the core and rotationally support the rotor;
a gas cooling system that circulates a cooling gas within the generator;
a variable pressure control system that variably a regulates a pressure of the cooling medium between zero (0) bar and two (2) bar relative to atmospheric pressure in accordance with a predetermined operational scheme; and
a low pressure frame that surrounds a plurality of the rotor and an entirety of the core and stator windings, the frame configured to operatively contain an internal pressure of two (2) bar relative to atmospheric pressure.
8. The generator of claim 7, wherein the variable pressure control system further comprises a controller and a pressurizing unit.
9. The generator of claim 8, wherein the controller is configured to receive a sensor signal representative of an output parameter of the generator.
10. The generator of claim 9, wherein the controller is further configured to determine an optimum operating pressure based on the predetermined operational scheme.
1 1 . The generator of claim 10, wherein the maximum operational efficiency of the generator is at a part-load condition.
12. The generator of claim 1 1 , wherein the maximum operational efficiency of the generator is between 20% to 80% of maximum power output.
13. The generator of claim 1 1 , wherein the maximum operational efficiency of the generator is between 50% to 70% of maximum power output.
14. The generator of claim 10, wherein the operative pressure of the cooling gas is a function of an output parameter of the generator.
15. The generator of claim 14, wherein the output parameter of the generator is a control room signal.
16. The generator of claim 15, wherein the output parameter of the generator is selected from the group consisting of terminal voltage, phase current demand, power factor and combinations thereof.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP15879245.7A EP3248275B1 (en) | 2015-01-21 | 2015-12-18 | Variable performance electric generator |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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US201562105798P | 2015-01-21 | 2015-01-21 | |
US62/105,798 | 2015-01-21 | ||
US14/938,330 US10141815B2 (en) | 2015-01-21 | 2015-11-11 | Variable performance electric generator |
US14/938,330 | 2015-11-11 |
Publications (1)
Publication Number | Publication Date |
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WO2016118266A1 true WO2016118266A1 (en) | 2016-07-28 |
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Application Number | Title | Priority Date | Filing Date |
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PCT/US2015/066554 WO2016118266A1 (en) | 2015-01-21 | 2015-12-18 | Variable performance electric generator |
PCT/US2015/066551 WO2016118265A1 (en) | 2015-01-21 | 2015-12-18 | A variable performance electric generator |
PCT/US2015/066564 WO2016118270A1 (en) | 2015-01-21 | 2015-12-18 | Method of achieving variable performance of an electric generator |
PCT/US2015/066555 WO2016118267A1 (en) | 2015-01-21 | 2015-12-18 | An improved life electric generator |
PCT/US2015/066558 WO2016118268A1 (en) | 2015-01-21 | 2015-12-18 | A variable performance electric generator |
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PCT/US2015/066551 WO2016118265A1 (en) | 2015-01-21 | 2015-12-18 | A variable performance electric generator |
PCT/US2015/066564 WO2016118270A1 (en) | 2015-01-21 | 2015-12-18 | Method of achieving variable performance of an electric generator |
PCT/US2015/066555 WO2016118267A1 (en) | 2015-01-21 | 2015-12-18 | An improved life electric generator |
PCT/US2015/066558 WO2016118268A1 (en) | 2015-01-21 | 2015-12-18 | A variable performance electric generator |
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US (5) | US10224787B2 (en) |
EP (6) | EP3248276B1 (en) |
HU (2) | HUE060646T2 (en) |
WO (5) | WO2016118266A1 (en) |
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DE102016217734A1 (en) * | 2016-09-16 | 2018-03-22 | Siemens Aktiengesellschaft | Rotor with coil arrangement and winding carrier |
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WO2018172153A1 (en) * | 2017-03-22 | 2018-09-27 | Siemens Aktiengesellschaft | Reduction of rotor winding wear of generators by measuring and controlling rotor winding temperature |
US10396630B2 (en) | 2017-06-23 | 2019-08-27 | Siemens Energy, Inc. | System and method for cooling windings of generator rotor |
US11128201B2 (en) | 2017-09-06 | 2021-09-21 | Ge Aviation Systems Llc | Method and assembly of a stator sleeve |
DE102019213866A1 (en) * | 2019-09-11 | 2021-03-11 | Siemens Energy Global GmbH & Co. KG | Regulation of the gas pressure in a generator below atmospheric pressure to increase efficiency |
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EP4307541A1 (en) | 2022-07-15 | 2024-01-17 | Siemens Gamesa Renewable Energy Innovation & Technology S.L. | Generator cooling |
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Also Published As
Publication number | Publication date |
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WO2016118268A1 (en) | 2016-07-28 |
EP3248276A4 (en) | 2018-09-19 |
WO2016118267A1 (en) | 2016-07-28 |
EP3224933A1 (en) | 2017-10-04 |
EP3248276B1 (en) | 2024-05-29 |
EP3248275B1 (en) | 2021-09-01 |
EP3248277A4 (en) | 2018-10-17 |
EP3248275A1 (en) | 2017-11-29 |
EP3248276A1 (en) | 2017-11-29 |
EP3248276C0 (en) | 2024-05-29 |
EP3248274A1 (en) | 2017-11-29 |
EP3248274B1 (en) | 2022-03-09 |
WO2016118265A1 (en) | 2016-07-28 |
US20160211721A1 (en) | 2016-07-21 |
EP3248275A4 (en) | 2018-10-10 |
EP3248277A1 (en) | 2017-11-29 |
US10224787B2 (en) | 2019-03-05 |
EP3224933A4 (en) | 2018-05-16 |
US10135320B2 (en) | 2018-11-20 |
US10141815B2 (en) | 2018-11-27 |
US10141816B2 (en) | 2018-11-27 |
HUE060646T2 (en) | 2023-04-28 |
US10044246B2 (en) | 2018-08-07 |
WO2016118270A1 (en) | 2016-07-28 |
US20160211725A1 (en) | 2016-07-21 |
US20160211722A1 (en) | 2016-07-21 |
EP3248277B1 (en) | 2022-12-07 |
US20160211726A1 (en) | 2016-07-21 |
EP3855605A1 (en) | 2021-07-28 |
EP3248274A4 (en) | 2018-10-03 |
US20160211724A1 (en) | 2016-07-21 |
HUE057261T2 (en) | 2022-04-28 |
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