Abstract:
A multi-pole protective device and system for electrical power transmission and distribution systems is provided that operates a multi-pole tripping system at ground level from a line-potential tripping device contained within each pole of the multi-pole system. The system includes multiple pole-unit assemblies each of which is totally self-contained and generates a tripping signal in response to overcurrent conditions to operate a ground-potential operating mechanism. In one arrangement, the pole units each include an internal line-potential tripping arrangement that communicates a trip signal to a ground-potential operating mechanism of the pole unit and associated pole units of the protective device arrangement. In a preferred arrangement, the line-potential tripping arrangement includes an insulated member that is moved to transmit the trip signal from line potential to ground potential.

Description:
This application claims the benefit of U.S. Provisional Application No. 60/186,699 filed on Mar. 3, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to the field of protective devices and systems for electrical power transmission and distribution systems, and more particularly to a protective device and system including a pole-unit protective device that provides tripping of interrupters on multiple poles from a line-potential tripping device of each of the pole-unit protective devices. 
     2. Description of the Related Art 
     Power transformers and other electrical equipment in the electrical power transmission and distribution field are connected to a power source through various switching and protection devices so as to provide the required desirable protection to the power transformers and electrical devices as well as desirable versatility and flexibility in supplying various load circuits in the electrical power system. For example various fuses, circuit-switchers and circuit breakers are known to provide this protection. 
     While the prior art arrangements may be useful to provide protective devices with various features, these prior arrangements do not provide desirable protection without extensive demands on space, cost and external controls and associated wiring. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is a principal object of the present invention to provide a multi-pole protective device and system for electrical power transmission and distribution systems that operates a multi-pole tripping system at ground level from a line-potential tripping device contained within each pole of the multi-pole system. 
     It is another object of the present invention to provide a protective arrangement including multiple pole-unit assemblies each of which is responsive to sensed overcurrents to provide a tripping signal to operate the multiple-pole unit assemblies. 
     It is a further object of the present invention to provide a protective device that is totally self-contained and that generates a tripping signal in response to overcurrent conditions to operate a ground-potential operating mechanism. 
     It is yet another object of the present invention to provide a protective device arrangement including multiple pole units that each include an internal line-potential tripping arrangement that communicates a trip signal to a ground-potential operating mechanism of the pole unit and associated pole units of the protective device arrangement. 
     It is a still further object of the present invention to provide a self-contained protective device pole-unit assembly that includes an interrupter, a ground-potential operating mechanism, and a line-potential trip arrangement for sensing overcurrents and operating the ground-potential operating mechanism to open the interrupter. 
     These and other objects of the present invention are efficiently achieved by the provision of a multi-pole protective device and system for electrical power transmission and distribution systems that operates a multi-pole tripping system at ground level from a line-potential tripping device contained within each pole of the multi-pole system. The system includes multiple pole-unit assemblies each of which is responsive to sensed overcurrents to provide a tripping signal. Each of the pole-unit assemblies is totally self-contained and generates a tripping signal in response to overcurrent conditions to operate a ground-potential operating mechanism. In one arrangement, the pole units each include an internal line-potential tripping arrangement that communicates a trip signal to a ground-potential operating mechanism of the pole unit and associated pole units of the protective device arrangement. Each pole unit also includes an interrupter operated by the ground-potential operating mechanism to open the interrupter. In such an arrangement, the pole units are mechanically independent of each other providing flexibility of location and ease of installation. Thus, the only interconnections between the pole units is the communication of the trip signal via electrical lines or the like. In a preferred arrangement, the line-potential tripping arrangement includes an insulated member that is moved to transmit the trip signal from line potential to ground potential. Also in a preferred arrangement, the movement of the insulated member generates a trip signal to operate the operating mechanism of the pole unit and associated pole units. In an alternate arrangement, the movement of the insulated member controls an electrical circuit to provide tripping signals to the pole units. In a particular arrangement, the operating mechanism of each pole unit is individually recharged manually via a tool affixed to a hot stick or the like. The recharging of the operating mechanism of each pole unit functions to close the interrupter thereof In a particular arrangement, the line-potential tripping arrangement of the pole unit is also reset during the recharging so as to be ready for tripping and operating the pole unit. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the specification taken in conjunction with the accompanying drawing in which: 
     FIG. 1 is a diagrammatic representation of a protective device and system in accordance with the present invention; 
     FIG. 2 is a diagrammatic representation of a protective device and system in accordance with an alternate embodiment of the present invention; 
     FIGS. 3 and 4 are perspective views, with parts cutaway for clarity, of an illustrative implementation of the protective device of FIGS. 1 and 2; 
     FIG. 5 is a partial perspective view, with parts cut away for clarity, of the protective device of FIGS. 3 and 4 illustrating an operating mechanism thereof; 
     FIG. 6 is a partial sectional view of FIG. 5 taken generally along the line  6 - 6  of FIG. 5; and 
     FIG. 7 is a partial sectional view of an interrupter of the protective device of FIGS. 3 and 4 illustrating a line-potential tripping arrangement thereof. 
    
    
     DETAILED DESCRIPTION 
     Referring now to FIG. 1, a protective system  15  of the present invention includes a plurality of pole units, e.g.  12 ,  14  and  16  corresponding to a respective pole of a multi-pole electrical power system. Each of the pole units  12 ,  14  and  16  includes an interrupter  20  having relatively movable contacts  17 ,  19 . The interrupter  20  is operated between open and closed positions by a ground potential operating mechanism  10  via an operating rod  24  that may also be characterized as an operating member. In the closed position, the interrupter  20  electrically connects a first circuit terminal at  21  to a second circuit terminal at  23 . In the open position, the interrupter  20  breaks the electrical path between the circuit terminals  21 ,  23 . In operation, the first and second circuit terminals at  21 ,  23  are energized at various electrical potentials with respect to the ground potential of the operating mechanism  10 . 
     A line-potential tripping arrangement  80 , which may also be characterized as a control arrangement, senses current flowing through the interrupter  20  and responds to predetermined overcurrent conditions to provide a trip signal. In a preferred arrangement, the trip signal is communicated via an insulated member  82  located within the interrupter  20  to ground potential in the vicinity of the operating mechanism  10  to operate a signal generator  84 . This can also be characterized as communicating, transferring or translating the trip signal via movement of the insulated member  82  to the vicinity of the operating mechanism  10  at ground potential. In a specific embodiment, the line-potential tripping arrangement  80  includes a magnetic latching solenoid device  81  that is pulsed at  83  by a control circuit  79  to release a stored energy device  85  that drives the insulated member  82 , e.g. upwardly in FIG.  1 . For example, a current-sensing transformer  77  provides a sensed current signal at  78  to a control circuit  79 . In response to the movement of the member  82 , the signal generator  84  provides an operating signal at  86 , e.g. in a specific embodiment, a pulse signal to operate the operating mechanism  10  of the pole unit  12  and the respective operating mechanisms  10   a,    10   b  of the associated pole units  14 ,  16 . The outputs  86   a,    86   b  of the signal generators  84   a,    84   b  of the associated pole units  14 ,  16  respectively are connected in parallel to each other and to the output  86  of the signal generator  84 . In a specific embodiment, the signal generator  84  is a so-called voice-coil generator of the type where a moving coil moves through a magnetic field to produce an output signal. In an arrangement for totally self-contained operation on a single-pole basis, the output  86  is connected directly to a latch tripping device  92  via the signal path  93 , tripping a latch at  94  to release the operating mechanism  10  and open the interrupter  20 . 
     In a preferred multi-pole arrangement, the combined output at  86  is connected through the series combination of interlock contacts  88 ,  88   a  and  88   b  of the pole units  12 ,  14  and  16  respectively. In order to ensure that the electrical circuits to the interrupters  20  are opened prior to closing the interrupters  20 , the interlock contacts  88 ,  88   a  and  88   b  are each enabled to provide a closed path when a respective disconnect switch  89 ,  89   a  and  89   b  that is connected in series with the respective electrical paths between the respective terminals  21 ,  23 ,  21   a,    23   a  and  21   b,    23   b  is open. The output  90  of the interlock switch contacts  88   b  is connected to an input of respective latch tripping devices  92 ,  92   a  and  92   b  of the respective operating mechanisms  10 ,  10   a  and  10   b.  For example, in a specific embodiment, the latch tripping devices  92 ,  92   a  and  92   b  are magnetic latching solenoids that are operated via a pulse signal at  90  to trip a latch at  94 ,  94   a  and  94   b  to release the respective operating mechanisms  10 ,  10   a  and  10   b,  opening the respective interrupters  20 ,  20   a  and  20   b.  In a specific embodiment, the operating mechanism  10  is a stored energy type. The operating mechanism  10  is recharged at  26  for the next opening operation, the interrupter  20  also being closed during the recharging of the operating mechanism  10  via the upward movement of the operating rod  24 . In a specific embodiment, the charging input at  26  is provided either via a lifting mechanism or rotation of a manual tool. In one specific embodiment, the line-potential tripping arrangement  80  is also reset during the recharging of the operating mechanism  10  and closing of the interrupter  20 . In another specific embodiment, either in addition to or in lieu of the resetting of FIG. 1, the line-potential tripping arrangement  80  is reset during the opening of the interrupter  20  via movement of the operating rod  24 , e.g. at  87 . 
     Referring now to the arrangement  11  of FIG. 2, upon tripping of any of the line potential tripping arrangements  80 ,  80   a  or  80   b  and movement of the respective insulating member  82 ,  82   a  or  82   b,  a respective contact  98 ,  98   a  or  98   b  is operated to provide electrical continuity with a battery or other power supply  102  via a circuit path  100  to energize the latch tripping devices  92 ,  92   a  and  92   b  at  91  through the interlock contacts  88 ,  88   a  and  88   b.  As illustrated in FIG. 2, local operating contacts at  106  are provided to energize the latch tripping devices  92 ,  92   a  and  92   b.  As noted in FIG. 2, while a power supply  102  is required, the signal generator  84  is not required. However, with reference now to FIGS. 1 and 2, it should be understood that the present invention also includes an arrangement where there is selectively utilized the input signals at  90  in FIG. 1 along with the input signals at  91  in FIG. 2, as noted by reference to the input  91  in FIG.  1 . 
     In accordance with additional features of the present invention and referring now to FIGS. 3 and 4, in an illustrative embodiment, the pole unit  12  is generally cylindrical shape overall including a generally cylindrical interrupter  20 , a generally cylindrical operating mechanism  10  and an insulating support column  108  intermediate the interrupter  20  and the operating mechanism  10 . The insulated member  82  is disposed through the insulating support column  108 . The operating member  24  is connected to an operating member  110  that is disposed through the insulating support column  108 . Thus, the overall pole unit  12  provides an internal, self-contained tripping system that communicates the trip function via the insulated member  82  to the operating mechanism  10 . Since the pole unit  12  is self contained, mounting of the pole unit is convenient and flexible such that only electrical connections are required between the pole units  12 ,  14  and  16 . 
     Considering additional aspects of the operating mechanism  10  and referring now additionally to FIGS. 5 and 6, the operating mechanism  10  includes a housing  22  that encloses one or more springs  30 ,  32 . The springs  30 ,  32  act between the housing  22  and a shuttle  36  that may also be characterized as a carrier or carriage. The shuttle  36  is attached to the operating rod  24 . The shuttle  36  is moved during charging at  26  to charge the springs  30 ,  32  and move the operating rod  24  to the closed position of the interrupter  20  as shown in FIGS. 1 and 3. A charging arrangement  27  includes a charging screw  25  (FIG. 6) that is rotated by the charging input  26 . The charging screw  25  drives a charging member  28 , e.g. a threaded nut, in response to the charging input at  26 , the charging member  28  contacting and moving the shuttle  36 . When the shuttle  36  and the operating rod  24  reach the closed position, a latch arrangement  40  is set to latch the operating rod  24  in a detent  42  against the stored energy in the springs  30 ,  32 . Thus, with the latch  40  set, the operating mechanism  10  is retained in the charged, closed position with stored energy in the springs  30 ,  32 . The latch arrangement  40  is generally disposed intermediate the springs  30 ,  32 . When the latch arrangement  40  is released, the shuttle  36  and the operating rod  24  move in response to the release of the energy stored in the springs  30 ,  32  to open the interrupter  20 . In the illustrative embodiment, the latch arrangement  40  is released via the operation of a solenoid  44 . The solenoid  44  acts against a secondary latch member  48  that holds a primary latch member  50  in the latched position. Upon movement of the secondary latch member  48 , the primary latch member  50  is released and releases the operating rod  24  from the detent at  42  via a latch roller member  43 . The operating rod  24  then moves to the open position, the open position of the operating rod  24  and the operating mechanism  10  being illustrated in FIG.  2 . The operating mechanism  10  is then again ready for charging via the charging input at  26 . The housing  22  of the operating mechanism  10  in a preferred embodiment provides a sealed environment containing a gas, e.g. an insulating gas such as SF 6 . This is advantageous in implementations where the interrupter  20  contains a pressurized gas such as SF 6 . In a preferred embodiment, the housing  22  is pressurized at the same pressure as the interrupter  20  such that no seals are required between the housing  22  and the circuit interrupter  20 . The pressurized housing  22  of the operating mechanism  10  provides a non-corrosive environment for the housed components of the operating mechanism  10  as well as reducing the sealing demands of the interrupter  20 . 
     Considering additional aspects of the tripping arrangement  80  and referring additionally to FIG. 7, the insulated member  82  is connected at  112  to the output  114  of the magnetic latching solenoid  81 . Along with the arrangement illustrated in FIG. 7, in lieu of the stored energy device  85  being located within the interrupter  20  adjacent the magnetic latching solenoid  81  of FIGS. 1 and 2, a driving spring  120  is provided about the insulated member  82  in the operating mechanism  10  as illustrated in FIG.  6 . The driving spring  120  acts between the housing  22  of the operating mechanism  10  and a widened portion  122  of the insulated member  82 . When the insulated member  82  is released by the magnetic latching solenoid  81 , the driving spring  120  is arranged to drive the insulated member  120  downward in FIG. 6. A lower portion  82 ′ of the insulated member  82  is affixed to an armature portion  124  of the signal generator  82  that moves within a magnetic core portion  126 . The lower portion  82 ′ of the insulated member  82  extends to the charging member  28  of the operating mechanism  10 . During the charging operation to charge the operating mechanism  10  and close the interrupter  20 , the charging member  28  drives the insulated member  82  via a resetting spring  128  that acts between the charging member and the insulated member  82 . 
     While there have been illustrated and described various embodiments of the present invention, it will be apparent that various changes and modifications will occur to those skilled in the art. Accordingly, it is intended in the appended claims to cover all such changes and modifications that fall within the true spirit and scope of the present invention.