Embodiments of the present invention relate generally to power distribution transformers, and, more particularly, to a distribution transformer having a power conditioning device integrated therewith.
Transformers, and similar devices, come in many different shapes and sizes for many different applications and uses. Fundamentally, all of these devices include at least one primary winding(s) with at least one core path(s) and at least one secondary winding(s) wrapped around the core(s). When a varying current (input) is passed through the primary winding a magnetic field is created which induces a varying magnetic flux in the core. The core is typically a highly magnetically permeable material which provides a path for this magnetic flux to pass through the secondary winding thereby inducing a voltage on the secondary (output) of the device.
Transformers are employed within distribution systems in order to transform voltage to a desired level and are sized by the current requirements of their connected load. If a load is connected to the secondary, an electric current will flow in the secondary winding and electrical energy will be transferred from the primary circuit, through the transformer, to the load. Transformers are designated by their power rating, typically in kVA, which describes the amount of energy per second that they can transfer and also by their primary and secondary operating voltages, typically in kV.
Transformers as described above can be connected to associated power electronics—with the power electronics being connected to the secondary to receive electrical energy therefrom and provide power conditioning thereto, such as controlling voltage, power factor and harmonics, for example. At present, such power electronics are provided separately from the transformer, with each of the power transformer and the power electronics being provided in its own dedicated housing and often being mounted on its own pad. Connections between the transformer and the power electronics are then made via the use of external cables that are close-coupled or separate to the transformer. For example, the external cables are often provided as underground connections that run between the transformer and the power electronics.
While the above described arrangement and connection of transformers and associated power electronics—within separate enclosures and on separate pads, being connected via external/underground cables—is sufficient for achieving a desired power transfer and power conditioning, it is recognized that such an arrangement/connection has drawbacks associated therewith. For example, it is recognized that the underground cables connecting the transformers and power electronics present an increased level of complexity and added cost to the low voltage connections of the distribution transformer front plate, with additional cables and low voltage terminals being required that crowd the connection compartment of the transformer. Additionally, the above described arrangement and connection of transformers and associated power electronics requires the purchase and installation (on separate pads) of separate pieces of equipment, with the non-standard installation of underground cables adding further to the cost/complexity of the installation.
Therefore, it would be desirable to provide a distribution transformer having a power conditioning device integrated therewith. Such an integrated unit would simplify the low voltage connections of the distribution transformer front plate and reduce the cost and complexity of purchase and installation of the transformer and its associated power electronics.
In accordance with one aspect of the present invention, a power system comprises a transformer including a fluid enclosure having a front plate, a rear plate, and side surfaces, the fluid enclosure configured to hold a transformer fluid therein, and a core and coil assembly positioned within the fluid enclosure so as to be immersed in the transformer fluid, the core and coil assembly including a transformer core and a plurality of windings wound about the transformer core. The power system also comprises a power conditioning device integrated with the transformer and connected thereto to receive an output power from the transformer, the power conditioning device including an electrical enclosure and a power conditioning circuit housed within the electrical enclosure and configured to perform power conversion and conditioning on the output power from the transformer. The power system further comprises a first set of electrical conductors coupled between the core and coil assembly and the power conditioning circuit to transfer the output power from the transformer to the power conditioning circuit and a second set of electrical conductors coupled between the power conditioning circuit and electrical connections on the front plate of the fluid enclosure, the second set of electrical conductors being routed through the fluid enclosure of the transformer.
In accordance with another aspect of the present invention, an enclosure unit for an integrated transformer—power conditioning system includes a fluid tank configured to house a core and coil assembly of a transformer therein, with the fluid tank further including a front panel having electrical fittings thereon, a pair of side panels, and a rear panel, wherein one of the front panel, the side panels, and the rear panel comprises a plurality of openings formed therein. The enclosure unit also includes an electrical enclosure configured to house a power conditioning circuit therein, the electrical enclosure comprising a mounting panel having a plurality of openings formed therein, the mounting panel of the electrical enclosure mounted to the one of the front panel, the side panels, and the rear panel of the fluid tank having the plurality of openings formed therein. The enclosure unit further includes a plurality of electrical connectors positioned in the plurality of openings formed in the mounting panel of the electrical enclosure and in the plurality of openings formed in the one of the front panel, the side panels, and the rear panel of the fluid tank, the plurality of electrical connectors providing for a first set of electrical conductors to pass out from the fluid tank into the electrical enclosure and a second set of electrical conductors to pass out from the electrical enclosure back into the fluid tank.
In accordance with yet another aspect of the present invention, an integrated transformer-voltage conversion system includes a transformer comprising a fluid tank comprising a front plate, a rear plate and side panels, a core and coil assembly positioned within the tank and including a transformer core and a plurality of windings wound about the transformer core, and a transformer fluid contained within the fluid tank and immersing the core and coil assembly. The system also includes a power conditioning device mounted on one of the front plate, the rear plate, or a respective side panel of the fluid tank, the power conditioning device electrically connected to the transformer to receive an output power therefrom and perform a power conditioning and conversion on the output power. The system further includes a first set of electrical conductors coupled between the transformer and the power conditioning device to transfer the output power from the transformer to the power conditioning device and a second set of electrical conductors coupled between the power conditioning device and electrical connections on the front plate of the fluid tank, wherein the second set of electrical conductors is routed through the fluid enclosure of the transformer so as to be immersed in the transformer fluid.
Various other features and advantages will be made apparent from the following detailed description and the drawings.
The drawings illustrate preferred embodiments presently contemplated for carrying out the invention.
In the drawings:
Embodiments of the invention are directed to a power system that includes a distribution transformer and a power conditioning device integrated therewith. Power conditioning electronics are provided on a back panel of the transformer, outside of the main transformer fluid enclosure in which insulating fluid is contained, with low voltage connections being routed through the fluid enclosure from the power conditioning electronics to connections on a front plate of the enclosure.
While an operating environment of an exemplary embodiment of such a power system is described below with respect to the system including a three-phase liquid-filled transformer, it is recognized that embodiments of the invention are not limited to such an implementation. That is, it is recognized that embodiments of the invention are not to be limited to the specific transformer configurations set forth in detail below and that all single-phase and three-phase transformers, voltage regulators, and distribution equipment are recognized to fall within the scope of the invention. According to additional embodiments, power conditioning electronics may be incorporated with medium transformers as well as large power, substation, solar power, generator step-up, auxiliary, auto, and grounding transformers, for example.
Referring to
Extending from the bottom of side edges of the enclosure 16 is a sill or risers 24 that includes sides and a front. Sill 24 is typically formed from a single piece of metal that is bent into the desired shape. Fluid enclosure 16 and riser 24 typically rest on a transformer pad 26 and are affixed thereto by bolts or the like. A cabinet door or other protective cover 28 may, in one embodiment, be pivotally attached to an upper edge of front plate 18 by means of hinges or the like and be configured to complement the space defined by riser 24 and front plate 18, so that when door 28 is closed, it rests on riser 24 and forms an interface with the fluid enclosure 16 and riser 24 and encloses electrical components extending through front plate 18. While the door or cover 28 is described above as being attached to an upper edge of front plate 18 and interacting with riser 24 to enclose the electrical components extending through front plate 18, it is recognized that the door or cover 28 may be provided in an alternative form. For example, door or cover 28 may be provided as a pair of doors that rotate outward on hinges located on side edges of front plate 18 or may be provided in other suitable forms or constructions that function to properly enclose the electrical components extending through front plate 18, with or without the use of a riser 24.
In one embodiment, one or more banks of corrugate 30 are provided on and as part of the enclosure 16—such that the enclosure 16 may be described as a “corrugated enclosure”—to provide for enhanced cooling of the cooling fluid therein. That is, a bank of corrugate 30 may be formed on one or more of sides 20 of enclosure 16, with each bank of corrugate 30 being formed of a plurality of cooling fins 32 that are welded to a wall of the enclosure 16 and spaced apart from one another a desired distance, with each of the cooling fins 32 having a hollow or semi-hollow construction, such that cooling fluid can be circulated therethrough from the enclosure 16.
As shown in
As shown in
Referring now to
The windings 46 disposed about magnetic core 44 are composed of a set of primary and secondary windings, with the sets of primary and secondary windings being connected in a known type of configuration. The windings 46 are formed from strips of electrically conductive material such as copper or aluminum and can be rectangular or round in shape, for example, although other materials and shapes may also be suitable. Individual turns of windings 46 are electrically insulated from each other by cellulose insulating paper (i.e., “Kraft paper”) to ensure that current travels throughout every winding turn and to protect the windings 46 from the high electrical and physical stresses present in the transformer.
As shown in
Referring now to
The electrical conductors 72 connect to/through bushings 74 and are routed to an input 76 of the power conditioning circuit 36 of power conditioning device 14. The power conditioning circuit 36 may operate according to known techniques to dynamically (or according to other known, controlled techniques) control and condition power received from the transformer 12 for output to a load or loads connected to system 10. The power conditioning circuit 36 may thus dynamically control voltage, power factor and harmonics to more effectively increase energy efficiency, manage peak demand, support sensitive customer equipment, and increase overall system reliability. The power conditioning circuit 36 may therefore provide functionality including, but not limited to: load voltage regulation, such as by directly boosting and bucking voltage across a wide range during forward and reverse power flow; sag/swell mitigation to protect sensitive loads from voltage sags and swells caused by disturbances on the grid; reactive power compensation to regulate power factor by dynamically injecting or absorbing reactive power; and harmonic cancellation to correct source current and load voltage harmonic distortion and reduce overall total harmonic distortion (THD).
As can be seen in
Upon being routed back into transformer 12, the second set of electrical conductors 78 is passed through the fluid enclosure 16 and through the electrically insulating transformer fluid 66 (i.e., immersed in the fluid 66). The electrical conductors 78 are routed through fluid enclosure 16 along a path that maintains an adequate separation between the conductors 78 and the core and coil assembly 42 (as well as any other components/devices within the enclosure, such as coolant circulation devices, for example), so as to ensure that no damage is done to the conductors 78. The electrical conductors 78 are then connected to a third pair of bushings 84 provided on the front plate 18 of fluid enclosure 16, with the bushings 84 providing electrical insulation and allowing the electrical conductors 78 to pass through the front plate 18. The bushings 84 on front plate 18 thus serve as electrical connections to the power system 10 and provide a conditioned, low voltage output that may be directly connected to a load or loads that receive power from the power system 10.
While the embodiment of
Referring now to
Beneficially, embodiments of the invention thus provide a power system that includes a transformer and a power conditioning device integrated therewith. Power conditioning electronics are provided on a plate/panel of the transformer (e.g., rear panel), outside of the main transformer fluid enclosure in which insulating fluid is contained, with connections being routed through the fluid enclosure from the power conditioning electronics to the front plate of the enclosure. The power conditioning device is mounted on a transformer plate/panel that is similar to the front plate used for the high voltage and low voltage connections of the transformer, with the plate/panel replacing a blank panel presently used on the existing transformer fluid enclosures, and with connections routed through the fluid enclosure. The incorporation of the power conditioning electronics with the transformer provides a conditioned output that may be directly connected to a load or loads that receive power from the power system, with no additional hardware/connections being required on the low voltage bushings of the transformer front plate and eliminate. The incorporation of the power conditioning electronics with the transformer also allows for the elimination of addition low voltage cabling in the transformer connection compartment that is typically required when the power conditioning device is separate and/or remote from the transformer, while also providing enhanced power quality, such as by compensating for sags, swells, and harmonics to prevent tripping of sensitive customer equipment and extend customer and utility asset life.
Therefore, according to an embodiment of the invention, a power system comprises a transformer including a fluid enclosure configured to hold a transformer fluid therein and having a front plate, a rear plate, and side surfaces, the fluid enclosure configured to hold a transformer fluid therein, and a core and coil assembly positioned within the fluid enclosure so as to be immersed in the transformer fluid, the core and coil assembly including a transformer core and a plurality of windings wound about the transformer core. The power system also comprises a power conditioning device integrated with the transformer and connected thereto to receive an output power from the transformer, the power conditioning device including an electrical enclosure and a power conditioning circuit housed within the electrical enclosure and configured to perform power conversion and conditioning on the output power from the transformer. The power system further comprises a first set of electrical conductors coupled between the core and coil assembly and the power conditioning circuit to transfer the output power from the transformer to the power conditioning circuit and a second set of electrical conductors coupled between the power conditioning circuit and electrical connections on the front plate of the fluid enclosure, the second set of electrical conductors being routed through the fluid enclosure of the transformer.
According to another embodiment of the invention, an enclosure unit for an integrated transformer—power conditioning system includes a fluid tank configured to house a core and coil assembly of a transformer therein, with the fluid tank further including a front panel having electrical fittings thereon, a pair of side panels, and a rear panel, wherein one of the front panel, the side panels, and the rear panel comprises a plurality of openings formed therein. The enclosure unit also includes an electrical enclosure configured to house a power conditioning circuit therein, the electrical enclosure comprising a mounting panel having a plurality of openings formed therein, the mounting panel of the electrical enclosure mounted to the one of the front panel, the side panels, and the rear panel of the fluid tank having the plurality of openings formed therein. The enclosure unit further includes a plurality of electrical connectors positioned in the plurality of openings formed in the mounting panel of the electrical enclosure and in the plurality of openings formed in the one of the front panel, the side panels, and the rear panel of the fluid tank, the plurality of electrical connectors providing for a first set of electrical conductors to pass out from the fluid tank into the electrical enclosure and a second set of electrical conductors to pass out from the electrical enclosure back into the fluid tank.
According to yet another embodiment of the invention, an integrated transformer-voltage conversion system includes a transformer comprising a fluid tank comprising a front plate, a rear plate and side panels, a core and coil assembly positioned within the tank and including a transformer core and a plurality of windings wound about the transformer core, and a transformer fluid contained within the fluid tank and immersing the core and coil assembly. The system also includes a power conditioning device mounted on one of the front plate, the rear plate, or a respective side panel of the fluid tank, the power conditioning device electrically connected to the transformer to receive an output power therefrom and perform a power conditioning and conversion on the output power. The system further includes a first set of electrical conductors coupled between the transformer and the power conditioning device to transfer the output power from the transformer to the power conditioning device and a second set of electrical conductors coupled between the power conditioning device and electrical connections on the front plate of the fluid tank, wherein the second set of electrical conductors is routed through the fluid enclosure of the transformer so as to be immersed in the transformer fluid.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
The present application is a non-provisional of, and claims priority to, U.S. Provisional Patent Application Ser. No. 62/373,687, filed Aug. 11, 2016, the disclosure of which is incorporated herein by reference in its entirety.
Number | Date | Country | |
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62373687 | Aug 2016 | US |