Abstract:
In a power line takeoff clamp assembly and method of use thereof an electrical power distribution line is clamped to a body of the clamp assembly. A power takeoff supported by the body clamped to the power line generates direct current from alternating current flowing in the power line. One or more sensors supported by the body clamped to the power line sense one or more values related to an electrical current flowing in a power line. A wireless transceiver supported by the body clamped to the power line communicates data regarding the one or more sensed values. Each sensor and the wireless transceiver utilize direct current generated by the power takeoff for the operation thereof.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 12/503,417, filed Jul. 15, 2009, which claims priority to U.S. Provisional Patent Application No. 61/081,881, filed Jul. 18, 2008, the disclosures of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a power line takeoff clamp assembly configured to be clamped about an electrical power distribution line. The clamp assembly houses a power takeoff (PTO) and a power line sense and communication module which derives its power from the PTO for sensing current flow in the electrical power distribution line and for radio transmitting data regarding the current flowing in the electrical power distribution line and/or a temperature of the electrical power distribution line. 
         [0004]    2. Description of Related Art 
         [0005]    The electric distribution grid in North America is characterized by aging infrastructure and outdated technology at a time when digital society demands an increased quantity and more reliable electrical power. As the investment cycle within the electricity distribution industry reaches a critical juncture for reinvestment in and optimization of the existing infrastructure, there is enormous pent-up demand to apply computer and electronics technologies in an industrial sector that has lagged the advancements made in the telecommunications, medical, aerospace, and manufacturing industries. 
         [0006]    Very little automation or monitoring typically exists between the customer meter and an electrical substation, making it difficult to quickly identify the cause and location of an electrical distribution problem, e.g., an outage, without manual dispatch of field crews. Additionally, planning and maintenance engineers in the electric utilities typically have limited information about the behavior of a circuit to drive the best decisions for circuit upgrade/rehabilitation tasks, and determining upgrade or replacement of equipment. 
         [0007]    An electric utility may have Supervisory Control and Data Acquisition (SCADA) capability allowing it to have centralized remote monitoring of circuit load immediately exiting a substation and perhaps a midpoint circuit reading. However, very few electric utilities have widely deployed SCADA systems, and those that do are only provided with circuit level information (entire circuit faulted and open) and cannot discern a fault location along the many miles a circuit typically spans. The utility depends on notification to their call center from customers to determine the location of damaged equipment during a power outage. Additionally, they will usually call customers to confirm restoration of power. 
         [0008]    Electrical distribution circuits are prone to temporary faults such as nearby lightning strikes, wind-borne debris, small animals climbing insulators, and the like. With a conventional circuit breaker or fuse, a transient fault opens the breaker or blows the fuse, de-energizing the line until a technician manually recloses the circuit breaker or replaces the blown fuse. Automatic reclosing devices (autoreclosers) often make several pre-programmed attempts to re-energize the line. If the transient fault clears, the circuit breaker will remain closed and normal operation of the power line will resume. If the fault is permanent (downed wires, tree branches lying on the wires, etc.) the autorecloser will exhaust its pre-programmed attempts to re-energize the line and remain tripped off until manually commanded to try again. Ninety percent of faults on overhead power lines are transient and can be cleared by autoreclosing, resulting in increased reliability of supply. 
         [0009]    Repeated manual closings into a permanent fault stress the circuit components, but this troubleshooting method is frequently employed by technicians. 
         [0010]    If the fault cannot be cleared by automated or manual closing into the fault, the next option is to send a troubleshooter into the field to identify where the problem/fault is located. If the troubleshooter can fix the problem upon arrival he will. If additional crews are required, the troubleshooter notifies the Operations Center dispatcher to send the appropriate crew (tree crew, underground crew, substation crew, etc.). When this situation exists, outage duration usually exceeds the 2 hour tolerance level of most customers. Service restoration is confirmed at the Operations Center via SCADA, through the automated distribution system, or by contacting customers. Currently, no automated system notification of power restoration exists throughout the distribution system. 
         [0011]    Additional devices may provide information on the location of a fault. So-called Fault Circuit Indicators (FCIs) have been used to identify when they have experienced a fault. FCIs are stand-alone devices and require visual inspection to determine their status via driving by the FCI location and looking for a color coded or blinking lighted indicator. 
       SUMMARY OF THE INVENTION 
       [0012]    Disclosed is a power line takeoff clamp assembly that includes communication electronics and sensors that are powered by current flowing in an electrical power distribution line to which the takeoff clamp assembly can be coupled. 
         [0013]    More specifically, the present invention is a power line takeoff clamp assembly that includes a body including a first housing and a second housing; means for moving the first housing and the second housing apart and together; means for sensing one or more values related to an electrical current flowing in a power line disposed between the first housing and the second housing when drawn together; means for wirelessly communicating data regarding the electrical current sensed by the means for sensing; and means for converting alternating current (AC) flowing in the power line into direct current (DC) that is provided to the means for sensing and the means for wirelessly communicating data for the operation thereof, wherein the means for sensing, the means for wirelessly communicating data, and the means for converting are supported by the body. 
         [0014]    The power line takeoff clamp assembly can further include means for clamping the power line between the first housing and second housing when said first housing and said second housing are moved together by the means for moving. 
         [0015]    The means for moving can include: a spring disposed between the first housing and the second housing for biasing the first housing and the second housing apart; and a screw disposed between the first housing and the second housing, said screw having male threads threadedly coupled with female threads of the means for clamping, wherein: rotating the screw in a first direction causes the first housing and the second housing to separate with the assistance of the spring bias; and rotating the screw in a second, opposite direction causes the first housing and the second housing to move together against the spring bias. 
         [0016]    The means for converting can include: a core made from a material in which magnetic flux can be established, said core having a first part in the first housing and a second part in the second housing; a wire wound about the first or second part of the core; a rectifier coupled to the wire and operative for rectifying AC induced on the wire into DC; and a capacitor for storing DC output by the rectifier. 
         [0017]    The means for converting can further include: a regulator disposed across the capacitor and operative for regulating a voltage on the capacitor; a current limit operative for detecting the DC output by the rectifier; a thermal reduction circuit responsive to the current limit detecting DC above a predetermined threshold for avoiding DC flowing into the capacitor; a diode disposed to block current from flowing from the capacitor into the thermal reduction circuit; and a processor operative for causing the thermal reduction circuit to avoid DC flowing into the capacitor in response to the thermal reduction circuit detecting DC above the predetermined threshold. 
         [0018]    The power line takeoff clamp assembly can further include means for guiding the power line into a space between the first housing and the second housing when said first housing and said second housing are apart. 
         [0019]    The means for guiding can include a projection which projects outward from the body. 
         [0020]    The projection can be part of a means for clamping the power line between the first housing and second housing when said first housing and said second housing are moved together by the means for moving. 
         [0021]    The power line takeoff clamp assembly can further include a channel formed in at least one of the first housing and the second housing for receiving the power line when said power line is disposed between the first housing and the second housing. 
         [0022]    The one or more values includes one or more of the following: a current induced in the wire by current flowing in the power line; a density of a magnetic flux produced in the core from current induced in the wire by current flowing in the power line; a density of a magnetic flux surrounding the power line produced by current flowing in the power line; an electric field produced by current flowing in the power line; and a temperature of the power line. 
         [0023]    The invention is also a power line monitoring method that includes: (a) clamping a body to an electrical power distribution line; (b) by way of means for generating supported by the body clamped to the power line, generating direct current from alternating current flowing in the power line; (c) by way of means for sensing supported by the body clamped to the power line that receives direct current for the operation thereof from the means for generating, sensing one or more values related to an electrical current flowing in a power line; and (d) by way of means for wirelessly communicating supported by the body clamped to the power line that receives direct current for the operation thereof from the means for generating, wirelessly communicating data regarding the one or more sensed values. 
         [0024]    Lastly, the invention is a power line takeoff clamp assembly that includes: means for clamping an electrical power distribution line to a body; means for generating direct current from alternating current flowing in the power line, wherein the means for generating is supported by the body clamped to the power line; means for sensing one or more values related to an electrical current flowing in the power line, wherein the means for sensing is supported by the body clamped to the power line and utilizes direct current from the means for generating for the operation thereof; and means for wirelessly communicating data regarding the one or more sensed values, wherein the means for wirelessly communicating data is supported by the body clamped to the power line and utilizes direct current from the means for generating for the operation thereof. 
         [0025]    The means for clamping can be operative for clamping the power line between a surface thereof and a surface of the body. 
         [0026]    The power line takeoff clamp assembly can further include means for causing sections of the body to open to receive the power line therebetween and for causing the sections of the body to close to secure the power line therebetween. 
         [0027]    The power line takeoff clamp assembly can further include means for guiding the power line into a space defined between the body sections when open. 
         [0028]    The means for guiding can comprise a projection outward from one of the body sections. The projection can be part of the means for clamping. 
         [0029]    The power line takeoff clamp assembly can further include an opening defined in the body for receiving the power line, said opening defined by the sections of the body when closed. 
         [0030]    The means for generating can include: a core made from a material where magnetic flux can be established, said core having parts that are separable for receiving the power line in an opening of the core defined when the core parts are together; a wire wound about at least one part of the core; a rectifier coupled to the wire and operative for rectifying into direct current alternating current induced on the wire by alternating current flowing in the power line disposed in the opening of the core; and a capacitor for storing direct current output by the rectifier. 
         [0031]    The means for generating can further include: a regulator operative for regulating a voltage on the capacitor; a current limit operative for detecting the direct current output by the rectifier; a thermal reduction circuit responsive to the current limit detecting direct current above a predetermined threshold and for avoiding direct current flowing into the capacitor when the detected direct current is above the predetermined threshold; a diode disposed to block current from flowing from the capacitor into the thermal reduction circuit; and a processor operative for causing the thermal reduction circuit to avoid direct current flowing into the capacitor in response to the thermal reduction circuit detecting direct current above the predetermined threshold. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]      FIG. 1  is a perspective view of a power line takeoff clamp assembly in accordance with the present invention clamped about an electrical power distribution line; 
           [0033]      FIG. 2  is a perspective view of the power line takeoff clamp assembly shown in  FIG. 1  in an open state; 
           [0034]      FIG. 3  is a front view of the power line takeoff clamp assembly of  FIG. 1  in the open state; 
           [0035]      FIG. 4  is another perspective view of the power line takeoff clamp assembly of  FIG. 1  in the open state; 
           [0036]      FIG. 5  is a top plan view of the power line takeoff clamp assembly of  FIG. 1 ; 
           [0037]      FIGS. 6-8  are open, partially closed, and fully closed sectional views of the power line takeoff clamp assembly of  FIG. 1  taken along lines A-A in  FIG. 5 ; 
           [0038]      FIGS. 9-11  are open, partially closed, and fully closed sectional views of the power line takeoff clamp assembly of  FIG. 1  taken along lines B-B in  FIG. 5 ; 
           [0039]      FIG. 12  is a view of the power line takeoff clamp assembly of  FIG. 11  with a rib of a clamp assembly thereof moved into contact with power line  4 ; 
           [0040]      FIGS. 13-15  are open, partially closed, and fully closed sectional views of the power line takeoff clamp assembly of  FIG. 1  taken along lines C-C in  FIG. 5 ; 
           [0041]      FIG. 16  is an electrical schematic of power line takeoff (PTO) electronics of the power line takeoff clamp assembly of  FIG. 3 ; and 
           [0042]      FIG. 17  is a block diagram of the electronics of the power line takeoff clamp assembly shown in  FIG. 3  including the PTO of  FIG. 16  and a power line sensing communication module. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0043]    The present invention will be described with reference to the accompanying figures where like reference numbers correspond to like elements. 
         [0044]    With reference to  FIG. 1 , a power line takeoff clamp assembly  2  in accordance with the present invention is configured to be clamped about an electrical power distribution line  4  (shown in phantom). 
         [0045]    With reference to  FIG. 2  and with continuing reference to  FIG. 1 , clamp assembly  2  is comprised of a first, upper housing  6  and a second, lower housing  8  that can be separated as shown in  FIG. 2  or drawn together as shown in  FIG. 1  by way of a threaded screw  10  in a manner described hereinafter. 
         [0046]    Lower housing  8  includes a first part  12  of a core  14  (shown best in  FIG. 13 ) made from a material in which magnetic flux lines can be readily established, such as, without limitation, a transformer core. First part  12  includes a pair of faces  16 ( a ) and  16 ( b ). As shown best in  FIGS. 13-15 , first part  12  of core  14  is generally U-shaped. However, this is not to be construed as limiting the invention since it is envisioned that first part  12  can be in the form of a half circle or any suitable and/or desirable shape that facilitates the use of core  14  in the manner described hereinafter. 
         [0047]    With reference to  FIG. 3  and with continuing reference to  FIGS. 1 and 2 , first part  12  of core  14  includes therearound a plurality of windings of a wire  18 . The ends of the windings of wire  18  are coupled to electronics  20  which comprise a power takeoff (PTO)  22  (shown schematically in  FIG. 16 ) and a power line sense and communications module  24  (shown schematically in  FIG. 17 ). 
         [0048]    Power line sense and communications module  24  includes a radio transceiver  26  which is coupled to an antenna  28  (shown best in  FIGS. 6-8 ) which is secured at its base to lower housing  8  and which projects through a sleeve  30 , upper housing  6  and an antenna cover  32  in the manner described hereinafter with reference to  FIGS. 6-8 . 
         [0049]    With reference to  FIG. 4  and with continuing reference to  FIGS. 1-3 , upper housing  6  houses a second part  34  of core  14  (shown best in  FIG. 13 ). Second part  34  of core  14  includes faces  36 ( a ) and  36 ( b ) which can move into contact or close proximity to faces  16 ( a ) and  16 ( b ), respectively, of first part  12  when upper housing  6  and lower housing  8  are moved together as shown in  FIG. 15 . As shown in  FIGS. 13-15 , second part  34  of core  14  is desirably U-shaped. However, this is not to be construed as limiting the invention since second part  34  of core  14  can be the form of a half circle or any other suitable and/or desirable shape. 
         [0050]    As shown best in  FIG. 4 , upper housing  6  includes a curved or arcuate channel  38  that is configured to receive power line  4  in the manner shown in  FIG. 3 . Lower housing  8  includes a curved or arcuate channel  40  that cooperates with channel  38  and a clamping assembly  42 , shown best in  FIGS. 9-12 , for clamping power line  4  when upper housing  6  and lower housing  8  are moved together in the manner described hereinafter. 
         [0051]    With reference to  FIG. 5  and with continuing reference to  FIGS. 1-4 , the closing of upper housing  6  and lower housing  8  together will now be described with reference to the cross-sections shown in  FIGS. 6-8  which are taken along section A-A in  FIG. 5 . 
         [0052]    With upper housing  6  and lower housing  8  in the fully open position shown in  FIG. 6 , antenna  28  extends through sleeve  30  and into antenna cover  32  where the distal end of antenna  28  is disposed intermediate the connection of antenna cover  32  to upper housing  6  and the end of antenna cover  32  opposite upper housing  6 . 
         [0053]    With reference to  FIG. 7  and with continuing reference to  FIGS. 1-6 , in response to moving upper housing  6  and lower housing  8  together, the end of sleeve  30  opposite lower housing  8  moves into upper housing  6  via an opening  44  therein. At the same time, the end of antenna  28  opposite lower housing  8  moves further into antenna cover  32  in the direction shown by arrow  46  in  FIG. 7 . 
         [0054]    With reference to  FIG. 8 , when upper housing  6  and lower housing  8  are fully moved together or closed, sleeve  30  is received within upper housing  6  and antenna  28  projects to its fullest extent into antenna cover  32  which acts as a barrier to the elements but permits the transmission and receipt of RF energy via antenna  28 . 
         [0055]    With ongoing reference to  FIG. 8  and with reference back to  FIG. 4 , clamping assembly  42  includes a so-called “duckbill” (or projection)  48  and one or more curved ribs  50  which, when upper housing  6  and lower housing  8  are in the fully closed position, press power line  4  into contact with channel  40  of lower housing  8  thereby clamping power line  4  between rib(s)  50  and channel  40  of lower housing  8 . The action of clamping assembly  42  to clamp power line  4  in this manner will now be described with reference to  FIGS. 9-12  which are cross-sections taken along lines B-B in  FIG. 5 . 
         [0056]    With reference to  FIGS. 9-12 , clamping assembly  42  includes duckbill  48  which facilitates the introduction of overhead power line  4  into channel  38  (as shown by the phantom power lines  4  and arrows  4 ′ in  FIG. 9 ) when mounting clamp assembly  42  to the power line  4  when upper housing  6  and lower housing  8  are in the open position shown in  FIG. 9 . 
         [0057]    The operation of clamp assembly  42  clamping power line  4  will now be described. 
         [0058]    As shown in  FIG. 9 , a coil spring  52  surrounds the threaded portion of threaded screw  10  and extends between a shoulder  54  of a guide assembly  56  that is operative for maintaining the alignment of upper housing  6  and lower housing  8 , especially the alignment of threaded screw  10  and the female threads of clamp assembly  42 . As shown best in  FIG. 10 , the lower end of spring  52  rests against shoulder  54  while the upper end of spring  52  is received in a circular slot  58  of clamp assembly  42 . The threaded end of screw  10  is mated with the female threads disposed in clamp assembly  42  coaxial with circular slot  58 . Clamp assembly  42  and guide assembly  56  are configured whereupon rotation of clamp assembly  42  relative to guide assembly  56  is avoided during rotation of screw  10  in the clockwise or counterclockwise direction. 
         [0059]    At a suitable time after power line  4  is received in channel  38 , a rotational force is applied about the longitudinal axis of screw  10  whereupon the threaded engagement of the male threads of screw  10  and the female threads of clamp assembly  42  cause clamp assembly  42  to be drawn toward lower housing  8  against the bias of spring  52 , which is operative for biasing upper housing  6  and lower housing  8  open in the absence of screw  10  drawing clamp assembly  42  toward lower housing  8 . 
         [0060]    As shown in sequence in  FIGS. 10-12 , rotating screw  10  in a first direction draws clamp assembly  42  and, hence, upper housing  6  toward lower housing  8  until upper housing  6  and lower housing  8  meet ( FIG. 11 ) and, optionally, faces  16 ( a ) and  16 ( b ) of the first part  12  of core  14  contact or come into close proximity to faces  36 ( a ) and  36 ( b ) of second part  34  of core  14 . 
         [0061]    As shown in progression in  FIGS. 11 and 12 , once upper housing  6  and lower housing  8  are in contact, continued rotation of screw  10  causes clamp assembly  42  to continue to move toward lower housing  8  whereupon one or more rib(s)  50  of clamp assembly  42  move into contact with and clamp power line  4  between said rib(s)  50  and the surface of channel  40 . 
         [0062]    Comparing  FIGS. 11 and 12 , it can be seen that clamp assembly  42  continues to travel toward lower housing  8  after upper housing  6  and lower housing  8  are in contact. Moreover, comparing  FIGS. 10 and 12 , it can be seen that the edge of rib(s)  50  that actually contact and actually clamp power line  4  in  FIG. 12  reside above the surface of channel  38  prior to causing clamp assembly  42  to clamp power line  4  between the surface of channel  40  and the lower edge(s) of rib(s)  50  in the clamp position. Thus, the ends of rib(s)  50  that actually clamp power line  4  continue to move below the level of the surface of channel  38  to effect clamping of power line  4  in  FIG. 12 . 
         [0063]      FIGS. 13-15  show a cross-section of clamp assembly  2  from the fully opened to the fully closed position taken along lines C-C in  FIG. 5 . 
         [0064]    Guide assembly  56  includes a slotted stationary member  60  affixed to lower housing  8  and a slidable member  62  attached to upper housing  6  and slidable within a slot (not shown) of stationary member  60 . 
         [0065]    As shown in  FIGS. 13-15 , in response to rotating screw  10  about its longitudinal axis, upper housing  6  and lower housing  8  move together until upper housing  6  and lower housing  8  touch and, optionally, faces  16 ( a ) and  16 ( b ) of first part  12  of core  14  contact or move into close proximity to faces  36 ( a ) and  36 ( b ) of second part  34  of core  14 . 
         [0066]    As shown in  FIG. 15 , upon rotating screw  10  to a sufficient extent, the end(s) of rib(s)  50  move into contact with power line  4  thereby clamping power line  4  to the surface of channel  40 . 
         [0067]    Surrounding each face  16 ( a ) and  16 ( b ) of the first part  12  of core  14  is a sealing means  64  that cooperates with a recess  66  in upper housing  6  surrounding each face  36 ( a ) and  36 ( b ) of the second part  34  of core  14 , as shown best in  FIG. 4 . As shown best in  FIG. 15 , when upper housing  6  and lower housing  8  are clamped together, each sealing means  64  forms with the corresponding recess  66  an environmental seal about the faces  16  and  36  of the first and second parts  12  and  34 , respectively, of core  14 . 
         [0068]    It is to be appreciated that the closing of upper housing  6  and lower housing  8  together described in connection with  FIGS. 6-8 ,  9 - 12 , and  13 - 15  described above can be reversed whereupon upper housing  6  and lower housing  8  can be moved to the fully opened position of clamp assembly  2  simply by rotating screw  10  in a direction opposite to the direction utilized to close upper housing  6  and lower housing  8  together. When opening upper housing  6  and lower housing  8  to the fully opened position, spring  52  acts to bias upper housing  6  and lower housing  8  to the open position, thus, aiding in the opening of upper housing  6  and lower housing  8  to the fully opened position. 
         [0069]    With reference to  FIGS. 16 and 17 , as discussed above in connection with  FIG. 3 , lower housing  6  houses electronics  20  comprising a power takeoff (PTO)  22  and a power line sense and communications module  24 . PTO  22  is designed to obtain and manage electrical power from power line  4 . Power is obtained via an inductive coupler and managed via electronic circuits and processor control described hereinafter. PTO  22  allows apparatus, such as power line sense and communications module  24 , to be directly powered from line  4  regardless of line voltage, thereby eliminating the need for a step-down transformer. 
         [0070]    The inductive coupler is formed from power line  4 , core  14  and the windings of wire  18  which are wound as secondary windings Ns 1  and Ns 2 . In the non-limiting embodiment described above, core  14  is formed from two individual U-shaped core pieces  12  and  34  that mechanically separate to allow core  14  to be clamped around power line  4 . When the core pieces are closed to form core  14 , power line  4  forms a single turn primary Np in combination with core  14 . Secondary windings Ns 1  and Ns 2  each include a number of turns that establish a suitable current ratio. 
         [0071]    The inductive coupler operates as a current transformer where the current flowing in power line  4  is transformed to secondary windings Ns 1  and Ns 2  by a ratio set by the turns ratio thereof. As discussed above, PTO  22  includes secondary windings Ns 1  and Ns 2  which allow the current ratio to be selected based upon power line current levels and the power needs of the apparatus that PTO  22  powers. PTO  22  also includes a thermal reduction circuit  70  that avoids excessive power dissipation by PTO  22 . Power is stored in so-called super capacitors  72  and  74  so that backup power and/or low-duty-cycle high-current applications can be supported. 
         [0072]    As discussed above, the inductive coupler operates as a current transformer with the windings Ns 1  and Ns 2  determining the current ratio relative to the current flowing in power line  4 . When PTO  22  is first energized, a switch SW 1  will be closed and a switch SW 2  will be open. This is performed automatically when PTO  22  is de-energized to allow a low ratio to be selected for fast charge times of super capacitors  72  and  74  via a full-wave rectifier  76 , a current limit  78 , and a diode  80 . While there is no functional limit on the number of secondary windings Ns 1  and Ns 2  for switches SW 1  and SW 2  that could be implemented, in practice, the number of windings Ns are typically limited by physical size. 
         [0073]    With current flowing in power line  4 , a magnetic field is set up in core  14  which induces a voltage in secondary windings Ns 1  and Ns 2 . With switch SW 1  closed and switch SW 2  open, AC current will flow in winding Ns 1  through switch SW 1 , through full-wave rectifier  76  which converts the AC current into DC current. DC current output by rectifier  76  flows through current limit  78 , through diode  80 , and into capacitors  72  and  74  and/or through a shunt regulator  82  and then returns to full-wave rectifier  76 . As would be appreciated by one skilled in the art, the magnitude of the current that flows through switch SW 1  is inversely proportional to the number of turns in Ns 1 . 
         [0074]    Desirably, DC current will flow into super capacitors  72  and  74  which will charge them and produce a voltage V 1 . When voltage V 1  reaches a desired level, shunt regulator  82  will shunt current away from super capacitors  72  and  74  halting the charge thus maintaining a constant voltage V 1 . Shunt regulator  82  includes for each capacitor  72  and  74  sensing circuitry Vsense that measures the voltage across the corresponding super capacitor and a switch, e.g., a MOSFET transistor, responsive to the output of Vsense for regulating the voltage across the corresponding super capacitor. Shunt regulator  82  prevents overcharging of super capacitors  72  and  74 , which typically have a limited voltage range. 
         [0075]    Voltage V 1  provides electrical power to other modules comprising electronics  20 , such as, without limitation, power line sense and communications module  24 . Voltage V 1  also provides a limited amount of electrical power to a processor  84  of PTO  22  and other supporting circuitry of PTO  22 . In response to the apparatus, e.g., module  24 , drawing power from super capacitors  72  and  74 , shunt regulator  82  will regulate the voltage level of voltage V 1  by bypassing or allowing super capacitors  72  and  74  to charge. Excess power not consumed by the apparatus is thermally dissipated by shunt regulator  82 . In operation, processor  84  monitors the current flowing through current limit  78  and causes thermal reduction circuit  70  to activate when the current flowing through current limit  78  is above a predetermining level. Thermal reduction circuit  70  includes a switch that closes to avoid current flowing through diode  80  and into capacitors  72  and  74 , and shunt regulator  82  thus significantly lowering the operating voltage of the secondary side of Ns 1  or Ns 2  thus lowering thermal dissipation. Diode  80  blocks current from back feeding from super capacitors  72  and  74  into thermal reduction circuit  70 . 
         [0076]    Processor  84  monitors voltage V 1  and also obtains a current reading from current limit circuit  78 . Based on these two readings, processor  84  determines when thermal reduction circuit  70  should be activated and for how long. When thermal reduction circuit  70  is operated, any apparatus power will be drawn from super capacitors  72  and  74  and the voltage will begin to drop since current is not being supplied to super capacitors  72  and  74 . Desirably, the signal to thermal reduction circuit  70  will be a pulse width modulated signal to keep voltage V 1  within predetermined bounds. 
         [0077]    Current limit circuit  78  is designed to provide a current reading to processor  84  and to fire a clamp circuit  86  if the current exceeds a design threshold. The purpose is to prevent damage to the components of PTO  22  during high current conditions. When clamp  86  fires, the secondary current produced from the series combination of Ns 1  and Ns 2  would set the ratio to the highest range (minimum secondary current) and lowers the voltage significantly thus setting the thermal dissipation to a minimum. Current limit circuit  78  operates on a per cycle basis so that as soon as the surge current condition is over, PTO  22  reverts back to normal operation. A benefit of operating current limit circuit  78  on a per cycle basis is that a portion of the current is allowed to continue to charge super capacitors  72  and  74 . All of this is desirably performed automatically without the intervention of processor  84  thus providing high reliability and fast response time. This is important for the case when PTO  22  is initially installed on a high current power line. Voltage V 1  is initially zero which means that processor  84  is not functioning. As noted above, a low ratio, e.g., Ns 1 , is initially selected which, on high current power lines, can easily exceed current limit circuit  78  causing clamp circuit  86  to fire thereby connecting Ns 1  and Ns 2  in series. If super capacitors  72  and  74  are not given a charge each cycle, PTO  22  would be stuck in this state. As it is, super capacitors  72  and  74  charge quickly which raises voltage V 1  and allows processor  84  to power up. Processor  84  makes a current reading from current limit  78  and, if appropriate, causes switch SW 2  to close and switch SW 1  to open thereby causing the series combination of Ns 1  and Ns 2  to supply electrical power to the remaining components of PTO  22 . 
         [0078]    Processor  84  determines the ratio to select, e.g., Ns 1  or the series combination of Ns 1  and Ns 2 , based on the present level of voltage V 1  and the current flowing through diode  80  as determined via current limit  78 . If a higher ratio is desired in order to lower the secondary current, switch S 2  is closed and switch S 1  is open whereupon the secondary ratio would then be the combination of Ns 1 +Ns 2 . In no event are switches SW 1  and SW 2  closed at the same time. To ensure this, the signal on line  88  is implemented as a single binary signal controlling both switch SW 1  and SW 2  with inverse logic. The ability to switch to a higher ratio secondary winding (Ns 1 +Ns 2 ) and the use of thermal reduction circuit  70 , enhances the accuracy of current reading by current limit  78  by lowering the flux swing in core  14 . 
         [0079]    Super capacitors  72  and  74 , shunt regulator  82 , current limit  78  and thermal reduction circuit  70  perform exactly the same whether Ns 1  alone or the series combination of Ns 1  and Ns 2  are supplying power thereto. Typically, processor  84  will switch to the series combination of Ns 1  and Ns 2  before enabling thermal reduction circuit  70  since operation at the series combination of Ns 1  and Ns 2  will typically lower thermal dissipation significantly. 
         [0080]    With reference to  FIG. 17 , PTO  22  can provide voltage V 1  to any suitable and/or desirable apparatus, including power line sense and communications module  24  shown in block diagram in  FIG. 17 . Module  24  can include a processor  90  coupled to one or more sensors  92  for detecting conditions on power line  4  either directly or indirectly. For example, sensors  92  can include a current sensor, a surge current sensor, a fault current sensor, an electric field sensor, and a line temperature sensor. The current sensor can be operative for providing to processor  90  an electrical value that represents the secondary current that flows in winding Ns 1  which is proportional to the current flowing in power line  4  as a function of the turns ratio of Ns 1 . The current sensor can be in the form of a resistor that processor  90  converts the voltage thereacross from an analog signal to a digital signal for processing thereby. 
         [0081]    The surge current sensor and fault current sensor can each be a Hall device which measures the magnetic field surrounding power line  4 . As discussed above, when upper housing  6  and lower housing  8  are closed, core  14  surrounds power line  4  and concentrates the magnetic field. This increase in flux density minimizes the errors introduced as the distance between power line  4  and the Hall devices vary due to line diameter variations. The surge current Hall sensor produces a voltage proportional to the flux density in core  14 . This voltage is converted to a digital signal via suitable analog-to-digital converter circuitry of processor  90 . 
         [0082]    Fault current sensing can be performed by another Hall device which measures a magnetic field surrounding power line  4 . This Hall device positioned at a known distance from power line  4  is utilized for fault currents, e.g., exceeding 1000 amps. The fault current Hall device produces a voltage proportional to the flux density surrounding power line  4  that is converted into a corresponding digital signal by analog-to-digital converter circuitry of processor  90 . 
         [0083]    The electric field sensor measures the electric field emanating from the power line via parallel plates disposed on opposite sides of power line  4 . The voltage impressed on these parallel plates can be converted into a digital signal by analog-to-digital converter circuitry of processor  90 . 
         [0084]    Lastly, the temperature sensor measures the temperature of power line  4 . It does this by being in close proximity to power line  4 . The temperature sensor produces a voltage proportional to the temperature which is converted into a digital signal by analog-to-digital converter circuitry of processor  90 . 
         [0085]    Desirably, module  24  includes all of the foregoing sensors. However, this is not to be construed as limiting the invention since it is envisioned that module  24  can include any one or combination of the sensors described above. 
         [0086]    Processor  90  can communicate the results obtained from each sensor via radio transceiver  26  and antenna  28 . The combination of processor  90 , radio transceiver  26 , and antenna  28  can also be utilized to receive data regarding sensor readings from other clamp assemblies in radio communication range and to forward said data readings to yet other clamp assemblies. Thus, two or more clamp assemblies  2  of the type described above can be utilized to form a network for communicating the status and operating characteristics of power lines  4  to which they are attached. The use of a plurality of clamp assemblies of the type described above in a network is disclosed in U.S. patent application Ser. No. 12/341,300, filed on Dec. 22, 2008, which is incorporated herein by reference. 
         [0087]    The invention has been described with reference to the preferred embodiment. Obvious modifications and alterations will occur to those of ordinary skill in the art upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.