Embodiments of the present invention generally relate to circuit breakers. More particularly, but not exclusively, embodiments of the present invention relate to circuit breakers having internal transient recovery voltage (TRV) capacitor assemblies that are coupled in parallel across the contacts of a circuit breaker.
Various types of circuit breakers used to selectively open and close electrical connections utilize a sealed enclosure or tank that is filled with a liquid or gaseous dielectric insulating medium, including, for example, sulfur hexafluoride (SF6), among other insulating gases and liquids. The dielectric insulating medium within the sealed enclosure can be used in at least an attempt to reduce and/or quench arcing, as well as prevent the flow of electrical current from electrically active parts and at least the enclosure, that can be associated at least with the opening of a contact of the circuit breaker. Moreover, such dielectric insulating mediums can be used in at least an attempt to prevent or quench arcing that can be associated with the operation of interrupters that are housed within the sealed enclosure of the circuit breaker, such as, for example, operation involving displacement of a moveable contact relative to a stationary contact of an interrupter.
Additionally, the opening of a contact of a circuit breaker, such as, for example, in response to a fault, can, in at least certain situations, result in the presence of relatively fast rising TRV across the contact of the circuit breaker contact, and, moreover, across the contacts of the circuit interrupter that is housed within the enclosure of the circuit breaker. Further, such TRV can attribute to unsuccessful interruption of the current, and thus, in at least certain situations, result in thermal/dielectric failure of the circuit interrupter.
Prior attempts to address TRVs in at least certain types of circuit breakers have included the use of external line-to-ground TRV capacitors. Yet, such external line-to-ground TRV capacitors typically require additional external mounting components and associated space, including for example, components for externally mounting of the external line-to-ground TRV capacitors to the circuit breaker or on a separate pedestal, which can increase manufacturing costs and expenses as well as potentially complicate providing sufficient clearance for at least certain components related to the circuit breaker. Additionally, external line-to-ground TRV capacitors are typically electrically coupled to only one side of the circuit breaker, and thus may not be effective for faults on both sides of the contact of the circuit breaker. Further, by being an external component, external line-to-ground TRV capacitors can be at relatively large distance from the contacts of the circuit breaker, which can adversely of the efficiency of the external line-to-ground TRV capacitors. Yet, attempts to address the adverse impact of such distances between external line-to-ground TRV capacitors and the contacts of the circuit breaker often involves use of capacitors having a relatively large capacitance, which can result in at least an increase in equipment cost.
An aspect of the present invention is a circuit breaker comprising an enclosure having an inner region and contacts housed within the inner region of the enclosure. A first side of the contact electrically can be coupled to a first electrical conductor of the circuit breaker, and a second side of the contact can be electrically coupled to a second electrical conductor of the circuit breaker. The circuit breaker can further include a capacitor assembly that can be housed within the inner region of the enclosure and connected in parallel across the contacts. Further, the capacitor assembly can include a transient recovery voltage capacitor.
Another aspect of an embodiment of the subject application is an apparatus comprising an enclosure having an interior region and a circuit interrupter that can be housed within the interior region of the enclosure. The circuit interrupter can have a first contact assembly and a second contact assembly, the first contact assembly comprising at least one moveable contact and a first shield, the second contact assembly comprising at least one stationary contact and a second shield. The at least one moveable contact can be configured to be (1) in contact with the at least one stationary contact when the circuit interrupter is in an electrically closed configuration, and (2) displaced from contact with the at least one stationary contact when the circuit interrupter is in an electrically open configuration. Additionally, the apparatus can include at least one capacitor assembly that can be housed within the interior region of the enclosure, the at least one capacitor assembly comprising a transient recovery voltage capacitor. Further, a first end of the at least one capacitor assembly can be in electrical contact with the first shield, and a second end of the at least one capacitor assembly can be in electrical contact with the second shield.
Additionally, an aspect of an embodiment of the subject application is an apparatus comprising at least one pole assembly having a first electrical conductor, a second electrical conductor, an enclosure, a circuit interrupter, and at least one capacitor assembly. The circuit interrupter and the at least one capacitor assembly can be housed within an interior region of the enclosure. Additionally, the at least one capacitor assembly can have a transient recovery voltage capacitor connected in parallel across a contact of the circuit interrupter.
The description herein makes reference to the accompanying figures wherein like reference numerals refer to like pans throughout the several views.
The foregoing summary, as well as following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings, certain embodiments. It should be understood, however, that the present invention is not limited to the arrangements and instrumentalities shown in the attached drawings.
Certain terminology is used in the foregoing description for convenience and is not intended to be limiting. Words such as “upper,” “lower,” “top,” “bottom,” “first,” and “second” designate directions in the drawings to which reference is made. This terminology includes the words specifically noted above, derivatives thereof, and words of similar import. Additionally, the words “a” and “one” are defined as including one or more of the referenced item unless specifically noted. The phrase “at least one of” followed by a list of two or more items, such as “A, B or C,” means any individual one of A, B or C, as well as any combination thereof.
For purposes of illustration,
The interior volume of the enclosure 24, as well as at least a portion of the entrance first and second bushings 16, 20, can be filled with a liquid or gaseous insulating medium 26 (
A variety of different types or styles of circuit interrupters 34 can be utilized with the circuit breaker 10, and can be at least partially, if not completely, housed within the sealed enclosure 24. For example, according to the illustrated embodiment, the circuit interrupter 34 comprises a puffer interrupter, as shown in at least
The first contact assembly 36 can include at least a moving side shield 56, a puffer piston 58, a puffer cylinder 60, a plurality of transfer contacts 62, and one or more moving contacts 64, such as, for example, a moving arcing contact 66 and a main moving contact 68. According to certain embodiments, the contact 74 of the circuit breaker 10 can comprise the one or more stationary contacts 44 of the second contact assembly 38 and the one or more moving contacts 64 of the first contact assembly 36 of the circuit interrupter 34. Additionally, according to certain embodiments, the moving side shield 56, which can be constructed from an electrically conductive material, such as, for example, aluminum or steel, among other materials, can be sized to house at least a portion of the components of the first contact assembly 36, and can include a first end cap 70 and a first body portion 72 that are directly or indirectly coupled together. Additionally, as shown in at least
The second contact assembly 38 can include at least a stationary side shield 42 and one or more stationary contacts 44, such as, for example, a stationary arcing contact 46 and a main stationary contact 48. According to certain embodiments, the stationary side shield 42, which can be constructed from an electrically conductive material such as aluminum or steel, among other materials, can be sized to house at least a portion of the components of the second contact assembly 38, and can include a second end cap 50 and a second body portion 52. Additionally, as shown in at least
According to the illustrated embodiment, when the contact 74 of the circuit breaker 10, and thus the circuit interrupter 34, is in the electrically closed position, the puffer cylinder 60 is at a linear position relative to at least the second contact assembly 38 and the puffer piston 58 such that the moving arcing contact 66 is in electrical contact with the stationary arcing contact 46, and the main moving contact 68 is in electrical contact with the main stationary contact 48. When the circuit breaker 10 is operated such that the contact 74 of the circuit breaker 10 is changed from an electrically closed position to an open position, the puffer cylinder 60 can be linearly displaced along at least a portion of the first contact assembly 36 and/or the insulator tube 40 such that the main moving contact 68 and moving arcing contact 66 disengage from being in contact with the main stationary contact 48 and stationary arcing contact 46, respectively, thereby at least attempting to generally terminate the stationary and moving contacts 44, 64 of the circuit interrupter 34 from being in electrical contact with each other.
As shown in at least
According to the illustrated embodiment, the mounting brackets 78a, 78b can be configured to be coupled to the adjacent first and second end caps 82a, 82b of an internal capacitor assembly 32 and the circuit interrupter 34. Such coupling of the mounting brackets to the internal capacitor assembly 32 and the circuit interrupter 34 can be achieved in a variety of different manners. For example, as shown in at least
The body portion 80 of the capacitor portion 76 can include art insulator tube 90 having a first tube end 92a and an opposing second tube end 92b, the first and second tube ends 92a, 92b being coupled to the adjacent first and second end caps 82a, 82b, respectively. The insulator tube 90 can comprise an insulation wall 94 having an outer surface 96 and an surface 98, the inner surface 98 generally defining an interior region 100 of the insulator tube 90. Further, the insulation wall 94 can be constructed from a variety of different electrically insulative materials, including, but not limited to, a hardened epoxy, among other materials. The interior region 100 of the insulator tube 90 can house at least the TRV capacitor 102. The TRV capacitor 102 is configured for mitigating transient recovery voltage (TRV) at least when the contact 74 of the circuit breaker 10, and thus the contacts 44, 64 of the circuit interrupter 34, are being changed from an electrically closed position to an electrically opened position. Moreover, the TRV capacitor 102 is configured to delay terminal fault and short line fault rate of rise of the initial TRV (ITRV) that can appear across the open contact 74 of the circuit breaker 10, and thus provides a time delay that assists in preventing the TRV level from reaching a level that could otherwise result in the failure of the circuit interrupter 34 to interrupt the circuit. The duration of the delay provided by the internal capacitor assembly 32 can be based on a variety of factors, including, for example, the capacitance value of the TRV capacitor 102.
According to certain embodiments, the TRV capacitor 102 can be an oil-filled capacitor, and thus the interior region 100 of the insulator tube 90 can be filled with oil, among other components of the TRV capacitor 102 that are housed within the interior region 100 of the insulator tube 90. Further, according to certain embodiments, the TRV capacitor 102 can also include an expansion element 104, such as, for example, a bellows, that may, or may not, be filled with a gas, such as, for example, nitrogen, among or compressible bodies. The expansion element 104 can be sized to be compressed in response to changes within the interior region 100 of the insulator tube 90, including, for example, changes in the temperature and/or pressure of the oil that is housed within the interior region 100 of the insulator tube 90.
The internal capacitor assembly 32, and thus the TRV capacitor 102, can be directly or indirectly in electrical communication with both the first and second electrical conductors 14, 18, including, but not limited to, when the contact 74 of the circuit breaker 10 is in an electrically open position. Thus, according to certain embodiments, the TRV capacitor 102 can be wired across, and in parallel to, the contact 74 of the circuit breaker 10, as indicated by at least
For example, according to certain embodiments, and as previously discussed, the mounting brackets 78a, 78b can be configured to secure one side of each of the internal capacitor assembly 32 to each side of the contacts 46, 66 of the circuit interrupter 34, and thus the contact 74 of the circuit breaker 10, such that the internal capacitor assemblies 32 run across, and parallel to, the contact 74 of the circuit breaker 10. For example, according to the illustrated embodiment, the first mounting bracket 78a of an internal capacitor assembly 32 can be attached to the moving side shield 56 of the circuit interrupter 34, while the other mounting bracket 78b of the internal capacitor assembly 32 can be attached to the stationary side shield 42 of the circuit interrupter 34. Further, according to certain embodiments, similar to the first and second end caps 82a, 82b of the internal capacitor assemblies 32, the mounting brackets 78a, 78b can also be constructed from an electrically conductive material, such as, for example, aluminum or steel, among other materials. Thus, according to at least certain embodiments, the TRV capacitor 102 of the internal capacitor assembly 32 can be in electrical communication with the first and second electrical conductors 14, 18 via the coupling of the first mounting and second brackets 78a, 78b with electrically conducive portions of the circuit interrupter 34 that are on either side of the contact. More specifically, according to the illustrated embodiment, the first mourning bracket 78a of the capacitor assembly 32 can be, via at least coupling of the first mounting bracket 78a to the moving side shield 50 of the circuit interrupter 34, be indirectly in electrical communication with the first electrical conductor 14. Similarly, the second mounting bracket 78b of the capacitor assembly 32 can be, via at least coupling of the second mounting bracket 78b to the stationary side shield 42 of the circuit interrupter 34, be indirectly in electrical communication with the second electrical conductor 18. However, the internal capacitor assemblies 32 can be configured to be in electrical communication with the first and electrical conductors 14, 18 in a variety of other manners such that the TRV capacitor 102 of the internal capacitor assemblies 32 is connected across, and parallel to, the contact 74 of the circuit interrupter 34. For example, according to other embodiments, the TRV capacitor 102 of the internal capacitor assemblies 32 can be, via wired connections, in electrical communication with one or more other components of the first and second contact assemblies 36, 38 of the circuit interrupter 34 such that the internal capacitor assemblies 32 remain in electrical communication with the first and electric it conductors 14, 18 regardless of whether the contact 74 of the circuit breaker 10 is in the open or closed position.
Referencing
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment(s), but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under the law. Furthermore it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary.
Filing Document | Filing Date | Country | Kind |
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PCT/US2019/067195 | 12/18/2019 | WO | 00 |
Number | Date | Country | |
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62786692 | Dec 2018 | US |