Patent Publication Number: US-2022224103-A1

Title: Dropout recloser

Description:
CROSS-REFERENCE RELATED TO APPLICATIONS 
     This application is continuation of prior U.S. application Ser. No. 16/866,656, filed May 5, 2020, which is continuation of prior U.S. application Ser. No. 14/399,534, filed Nov. 9, 2014, which is a national stage entry of International Application Number PCT/2013/039857, filed May 7, 2013, which claims priority of U.S. Application No. 61/643,593, filed May 7, 2012, which are all hereby incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     This patent relates to electric transmission and distribution system fault detection, fault isolation and protection devices, sectionalizers and reclosers, and in particular, this patent relates to self-reclosing, dropout recloser devices and methods. 
     BACKGROUND 
     U.S. patent application Ser. No. 12/095,067, filed Jul. 16, 2008, the disclosure of which is hereby incorporated herein by reference and commonly assigned to the owner of this patent describes a fault interrupting and reclosing device of a self-contained design. The device conveniently fits within conventional cutouts, provides fault detection and fault interruption, reclosing/service restoration and dropout sectionalizing lock out with a visible gap. A corresponding commercial product is the dropout recloser marketed and sold by S&amp;C Electric Company of Chicago, Ill., United States of America under the trademark TripSaver®, which has received broad acclaim being named a winner of the 2008 R&amp;D 100 Awards Competition and a winner of the 2007 Chicago Innovation Awards Competition as well as having commercial success. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a dropout recloser according to herein described embodiments electrically coupled within a cutout. 
         FIG. 2  is a side view of the dropout recloser shown in  FIG. 1 , in a dropout position. 
         FIG. 3  is side perspective view of the dropout recloser shown in  FIG. 1 , the housing portion thereof being depicted in phantom to reveal components disposed therein. 
         FIG. 4  is a side perspective view of the dropout recloser shown in  FIG. 1  with the housing portion removed to reveal the internal components of the dropout recloser. 
         FIG. 5  is a side view of the dropout recloser shown in  FIG. 1  with the housing portion removed to reveal the internal components of the dropout recloser. 
         FIG. 6  is a view taken along lines  6 - 6  of  FIG. 5  depicting a bottom housing portion of the dropout recloser and a display device disposed therein. 
         FIG. 7  is a side perspective view of a trunnion that may be used in the dropout recloser of  FIG. 1 . 
         FIG. 8  is an enlarged view of the trunnion shown in  FIG. 7  disposed within a lower contact assembly of a cutout. 
         FIG. 9  is a side view of an actuator suitable for use in various devices including a dropout recloser as depicted in  FIG. 1 . 
         FIG. 10  is a perspective view of the actuator depicted in  FIG. 9 . 
         FIG. 11  is a graphic illustration of the actuator depicted in  FIG. 9  in a first position. 
         FIG. 12  is a graphic illustration of the actuator depicted in  FIG. 9  in a second position different than the first position shown in  FIG. 11 . 
         FIG. 13  is a graphic illustration of a partial perspective view of the actuator depicted in  FIG. 9 . 
         FIG. 14  is a graphic illustration of a section view of the actuator depicted in  FIG. 9 . 
         FIG. 15  is a graphic illustration of a section view of an alternate embodiment of the actuator depicted in  FIG. 9 . 
         FIG. 16  is a circuit to determine the position of an actuator such as the actuator depicted in  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  depicts a dropout recloser  100  (referred to herein either as the dropout recloser  100  or the recloser  100 ) coupled within a cutout  102 . The cutout  102  is of conventional construction as such as the Type XS Cutout available from S&amp;C Electric Company, Chicago, Ill., USA. The cutout  102  includes a mounting  104 , an insulator  106 , first spring biased contact  108  and second hinge contact  110 . The hinge contact  110  includes a hinge portion  112  formed with a pivot receiving slot  114  with an integral retaining structure  116 . The cutout  102  is depicted and described to facilitate the following discussion of the structure and operation of the dropout recloser  100 . 
     The recloser  100  includes a housing  120  for the recloser  100 . The housing  120  may be a unitary structure or an assembly of housing portions. As shown the housing  120  includes first and second portions. The recloser  100  includes a trunnion or terminal  122  including a pivot  124 . The trunnion  122  extends from a side portion as depicted in the drawing of the housing  120 . The recloser  100  also includes a post-like contact or terminal  126  disposed at an upper portion as depicted in the drawing of the housing  120 . The hinge portion  112  and in particular the pivot receiving slot  114  receives the trunnion  122  and pivot  124  and the spring-biased contact  108  engages the contact  126  to secure the recloser  100  in the cutout  102  and electrically couple the recloser  100  to the cutout  102 . 
     The recloser  100  is a dropout recloser. A dropout recloser is capable of in accordance with its operating programming after a predetermined number of fault interrupting operations, e.g., 1, 2, 3 or more but typically 3, to drop out of the cutout  102  and hang freely in the hinge contact  110  providing sectionalization with an observable visible gap. As will be described, the recloser  100  includes fault interrupting and reclosing components, a drop out mechanism and a controller. The drop out mechanism coupled to the trunnion  122  allows translation and/or articulation of the entire recloser  100  relative to the trunnion  122  in the direction of arrow “A” in  FIG. 1 . This motion of the recloser  100  releases the contact  126  from contact  108  freeing the recloser  100  to rotate about pivot  124  in the hinge  112 .  FIG. 2  reflects the recloser  100  after this action of releasing the recloser  100  from the cutout  102  to a dropout position. 
       FIGS. 3-5  are illustrations of the operative components of the recloser  100  internal to the housing  120 . An advantage of the recloser  100  is that in addition to the fault isolation/reclosing components, the drop out mechanism except for the portion of the trunnion  122  extending outwardly from the housing  120  are contained within the housing  120 . Hence, the recloser  100  enjoys excellent weather resistance. A seal  132  and seal garter  134  provide weather-tight sealing of the housing  120  where the trunnion  122  extends through. 
     The contact  126  extends through a bushing  138  that is formed integrally with a D-ring handle  140  and a bump stop  142  fitted with an insulating bumper  144 . Extending through the bushing  138  the contact  126  is electrically coupled to a first side  150  of a vacuum interrupter  152  secured within the housing  120  by threaded fasteners  154  engaging a vacuum interrupter guide structure  155  with boss structures  156  formed within the housing  120 . In this manner, the contact  126  is coupled to a stationary contact (not depicted) of the vacuum interrupter  152 . A flexible contact assembly  160  electrically couples a moving contact (not depicted) of the vacuum interrupter  152  and hence the contact  126  internally within the housing  120  to a power supply and sensing assembly  166  and via a terminal structure  162  (an intermediate flexible conductor not depicted) and from the assembly  166  via a conductor  168  to the trunnion  122 . 
     The moving contact of the vacuum interrupter  152  is coupled to an actuating rod  170  that extends within the housing  120  to an actuator  172 . A bias spring  176  engages the rod  170  and provides a bias force on the rod  170 . Described later, the actuator  172  may be a dual coil, bi-stable electro-magnetic solenoid. 
     A main frame plate  180  secured within the housing  120  provides a foundation for secure mounting of the power supply and sensor assembly  166 , the actuator  172 , an electronic control module  186  and a dropout assembly  190 . A seal  193  ensures weather-tight sealing of the housing  120  about the main frame plate. A magnetic control switch assembly  191  is coupled to the control module  186  and is actuated via a selector  130 . The control module further couples to a display  198  ( FIG. 6 ). 
     The recloser  100  is designed to manage operating voltages up to or potentially in excess of 34.5 kV, and fault currents up to or potentially in excess of 4000 A. Suitable conducting and insulating materials are therefore selected for its construction. 
     The dropout assembly  190  includes two mutually engaging operating members  192  and  194  mounted on pivots  196  and  198 . A solenoid actuator (not depicted) engages the member  192 . The member  194  couples to an articulating trunnion mount  200 . The actuator drives members  192  and  194  to release tabs  202 . Under the weight of the recloser  100 , the members  192  and  194  rotate with the members  192  and  194  sliding along the surfaces  204  and  206 . The trunnion  122  articulates responsive to its coupling to the member  194  and the recloser  100  translates relative to the cutout  102  allowing for dropout for the recloser  100  from the coupled position as depicted in  FIG. 1  to the dropout configuration as depicted in  FIG. 2 . 
     To control and limit the rotating motion of the reclosure  100  during dropout, the pivots  124  may be formed with motion limiting structures  210 . The structures  210  may be radially extending arms formed integral with the pivots  124 . 
     Best seen in  FIG. 8 , the structures  210  engage the retaining structures  116  of the hinge slots  114  limiting the arc through which the recloser  100  moves during dropout. The recloser  100  does not stop abruptly upon engagement of the structures  210  with the structures  116 ; however, and the recloser  100  advantageously utilizes its weight to provide slow rotation and provide damping. As the structures  210  engage the structures  116  they lever the trunnion  122  in a motion translating the trunnion  122  and hence the recloser  100  in the hinge slot  114 . This motion is depicted in phantom in  FIG. 8 . Causing the recloser  100  to lift its own weight on dropout quickly dissipates the energy of dropout. 
     As an alternative to the radial arms  210  depicted in  FIGS. 7 and 8 , pins may be fitted to the trunnion  122  or other structures that ultimately engage the a portion of the hinge slot  114  to dissipate energy of dropout and hence reduce rotational travel and oscillation. 
       FIG. 7  also illustrates the connecting boss structure  212  of the trunnion  122  that extends into the housing  120  and allows coupling to the dropout mechanism. A threaded fastener ( FIGS. 3-5 ) may be used to secure the trunnion  122 . The trunnion  122  may also be formed with a hook loop  214  to facilitate placement of the recloser  100  in the cutout  102  using a conventional hook stick. 
     The recloser  100  utilizes the actuator  172  to drive the moving contact of the vacuum interrupter  152  from a make position to a break position and vice versa. This is accomplished via exertion of axial force to the connecting rod  170 . The actuator  172  may be a device having two stable states corresponding with the contact make and contact break positions of the vacuum interrupter  152 , i.e., latching ability, while still providing sufficient driving force to break the contacts of the vacuum interrupter  152  under fault current conditions and to make the contacts quickly. 
     Actuator 
     The actuator  300  illustrated in  FIGS. 9-15  may be used in the recloser  100 . The actuator  300  is of the bi-stable-type operators, and embodies pole pieces that transmit flux to the operator from one or more flat magnets. Flat magnets are easy to manufacture and magnetize. The actuator  300  also stabilizes and locates the magnets and pole pieces within a molded cavity of a common coil bobbin without the need for glues or adhesives. Structures of bi-stable actuators and theory of operation are described in Appendix A. 
     As shown in the figures, actuator  300  includes two pole pieces  302  and  304  concentrating two permanent magnets  306  and  308 , for example suitable permanent magnets include NdFeB magnets, around an operator/plunger  310 . Two coils  312  and  316  ( FIG. 9 ), for example suitable coils include 250T coils, mounted on a single bobbin  318  within a frame  320  toggle the plunger  310  between stable states. The frame may be a simple structure of 4 plates of suitable metal or non-metallic structural material. The actuator  300  latches at each end of its stroke ( FIGS. 11 and 12 ) and provides forces to toggle from one end to the other as well as to drive a load. The coils  312  and  316  toggle lines of flux from the magnets  306  and  308  from one end of the plunger  310  to the other. 
     The coil bobbin  318  embodies a linear bearing surface to guide, support and constrain the moving plunger  310  while preventing a frictional interface at the center magnetic pole face interface where it would otherwise form a friction brake preventing movement. Alternatively or additionally a non-stick surface such as a Teflon® or other non-slip surface may be used to allow proper operation of the actuator  300 . 
     The pole pieces  302  and  304  have a generally square frustum cuboid configuration with a convex face surfaces  330  and  332  and square planar base surfaces  334  and  336 . The square planar base surfaces  334  and  336  correspond generally in shape with the square planar face surfaces of the magnets  306  and  308 . The square frustum cuboid configuration of the pole pieces  302  and  304  acts to concentrate magnetic flux of the magnets  306  and  308  about the plunger  310 . The pole pieces may be constructed from any suitable magnetic flux concentrating material. Suitable materials will have high magnetic permeability and low power loss. These materials include, for example, ferrous metals and their alloys in laminate, homogenous, matrix or any other suitable form. 
     As is appreciated, the actuator  300  utilizes inexpensive flat magnets  306  and  308  to avoid difficulties of using radially charged magnets and gains the freedom of choosing from a wider range of magnet area, length and pole face area than the existing direct magnet face allows. 
     Actuator  300  uses a fully encompassing center pole area  340  which reduces losses incurred by other approaches. By surrounding a high percentage of the periphery of the moving component, the operator/plunger  310  the pole piece(s)  302  and  304  reduce the losses due to leakage and avoid the limitations of area to plunger face ratios A magnet area of (for instance) five square inches can be efficiently applied to three square inches of the moving part with whatever shape may be desired for the transfer of the flux. 
     Virtually any number of pole pieces may be used.  FIGS. 9-14  illustrate structures using two pole pieces, pole pieces  302  and  304 .  FIG. 15  illustrates an actuator  400  that utilizes four pole pieces  402 ,  404 ,  406  and  408  coupling magnets  410 ,  412 ,  414  and  416  acting on an operator  418 . The four pole pieces  402 ,  404 ,  406  and  408 , magnets  410 ,  412 ,  414  and  416  and operator  418  are retained within a bobbin  420  for coils (not depicted). 
     Position Detection 
     The actuator  172  used in the recloser  100  and the actuator  300 , a particular embodiment of an actuator that may be used in the application provided by the actuator  172 , has two stable positions. In operation, it may become necessary to determine the position of the actuator. By extension, in the recloser  100 , the position of the actuator  172  corresponds to the make or break position of the moving contact of the vacuum interrupter  152 . One solution is to provide a sensor that senses actuator position. This solution adds cost and complexity. It would be preferable to determine the position of the actuator without adding a sensor or other device. 
     In the embodiments of the actuators described herein, and in connection with other similarly constructed actuators, two coils are used to drive the actuator between its two stable positions. For example, in the actuator  172 , two coils are used to drive the actuator between the make and break contact vacuum interrupter  152  contact positions and in the actuator  300 , two coils  312  and  316  are used to drive the actuator between its two stable positions. 
       FIG. 16  provides a circuit schematic of a two coil, two position bi-stable actuator. A tap  500  is provided between first coil  502  and second coil  504  (inherent resistance also being represented). A pull down resistor is coupled at tap  500 . Switch structures  506 ,  508 ,  510  and  512  allow for selectively energizing coils  502  and  504  to operate the actuator. The switches  506 ,  508 ,  510  and  512  also allow for selectively pulsing the coils  502  and  504  as described to determine position of an operator of the actuator. Voltage sensing is provided at tap  500 , and voltage and current sensing is provided as applied to the actuator, i.e., the coils. Circuit capacitance is also represented in the figure. 
     To determine operator position, a short voltage pulse (or current pulse) is applied to the coils  502  and  504 . The relative coil response shows which coil has the open gap, and hence the position of the operator. 
     As depicted in  FIG. 16 , the two series connected coils  502  and  504  are of equal coil construction. A short pulse of coil power is applied and the center tap between the coils is sensed for relative voltage. The coil with the higher voltage drop has the closed magnetic gap. Of course the coils may be of different design, e.g., different numbers of or types of windings. With such coils it is a matter of calibrating to determine the indicative voltage drops. 
     One example of the ways to perform the position check is to apply the coil power for ¼ millisecond while measuring the relative voltage at the center tap  500  between the series coils  502  and  504 . The coil ( 502  or  504 ) with the closed gap will have a voltage greater than ½ of the applied voltage. The short time during which voltage or current is applied to the coils  502  and  504  is below the minimum mechanical response time to affect operation. The coil polarity may also be chosen to drive the actuator into its existing position, i.e., close a closed actuator or open an open actuator. The existing actuator position may be based on either the last measured position, or last open or close command. To virtually eliminate the possibility that the actuator will change state, the pulse duration is to be a very short percentage of the pulse time required to release the actuator. For example, a ¼ millisecond pulse could be used when the minimum pulse time needed to reduce the holding force to a release level is greater than 5 milliseconds. For this example less than 5% of the release pulse duration. 
     In the recloser  100 , a three wire connector  240  couples the actuator  172 , i.e., the two coils and the center tap, to the controller  186  for operating the device. The controller  186  is programmed to provide the various operating sequences such as fault trip, reclose, fault trip, drop out; one trip to drop out; operations count, vacuum interrupter end-of-service-life determination, and the like. The various operating modes are selected by manipulation of the arm  130  and the magnetic switch  191 . Additionally, device operating mode, status and the like may be indicated on the display  198 . 
     Hence, manipulation of the arm  130  may cause the controller  186  to display in scroll fashion various device information to the display or manipulation of the arm  130  may allow selection of displayed information. Additional manipulation of the arm  130  may allow setting or modification of device operating parameters. For example, the device may be set to operate in standard reclose mode (1 or more reclose attempts before sectionalizing), sectionalize mode (sectionalize on first fault indication), fault withstand mode, and the like. 
     A fault withstand mode may be invoked when the recloser  100  detects fault current in excess of the interrupting rating capability of the device. In this situation, the recloser  100  may maintain its state, i.e., the device remains in a closed state until an indication that other protective devices, e.g., an upstream breaker has operated. Upon detecting that an upstream device has operated, e.g., by detecting loss of voltage, to cause the recloser  100 , to dropout during this interval. Alternatively, the device may be set to fault count, i.e., to determine that a selectable/lettable number of excess fault current situations have occurred and then to dropout during a next suitable open interval. Detection of fault current at or below the current interrupting rating of the recloser  100  allows it to operate in accordance with its current operating settings.