Abstract:
A device connectable to an electric power line conductor including an electrically conductive insulated wire wound at least twice. A first end of the wire is configured to be connected to a first power line conductor and a second end of the wire is configured to be connected to a second power line conductor. A housing is mountable to the wire and includes an iron core power supply transformer configured to surround the wire to power a power supply module.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The application claims priority to U.S. Provisional Application No. 61/740517 which was filed on Dec. 21, 2012. 
     
    
     BACKGROUND 
       [0002]    The present disclosure relates to a multiple parameter sensor-transmitter/receiver unit which may be installed on or removed from an energized electric power line, such as an overhead power line. With the advent of Smart-Grid applications for electric power systems, there is an ever increasing need for a device that measures electric, mechanical, and environmental parameters of the power line. 
         [0003]    In order to address the increasing need for monitoring power lines, devices have been developed that attach directly to the power line. These devices generally require a power source, such as batteries or solar panels. When utilizing batteries, regular maintenance must be performed to replace the batteries, which can become costly. When solar panels are used, the device may only be powered during sunny weather conditions and during daylight hours. Therefore, there is a need for a device which is low maintenance and can be constantly powered independent of weather conditions over a wide range of current levels in the power line. 
       SUMMARY 
       [0004]    A device connectable to an electric power line conductor including an electrically conductive insulated wire wound at least twice. A first end of the wire is configured to be connected to a first power line conductor and a second end of the wire is configured to be connected to a second power line conductor. A housing is mountable to the wire and includes an iron core power supply transformer configured to surround the wire to power a power supply module. 
         [0005]    A device connectable to an electric power line conductor including a loop tube providing a form and at least two turns of electrically conductive and insulated wire surrounding the loop tube configured to be connected in series with a first electric power line conductor and a second electric power line conductor. 
         [0006]    These and other features of the disclosed examples can be understood from the following description and the accompanying drawings, which can be briefly described as follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  illustrates an STR unit mounted on a low threshold current power supply (“LTPS”). 
           [0008]      FIG. 2  illustrates a front view of the LTPS of  FIG. 1 . 
           [0009]      FIG. 3  illustrates a cross-sectional view taken along line B-B of the LTPS of  FIG. 2 . 
           [0010]      FIG. 4  illustrates a cross-sectional view taken along line A-A of  FIG. 2 . 
           [0011]      FIG. 5  illustrates an enlarged detail of circle A in  FIG. 4 . 
           [0012]      FIG. 6  illustrates a right side view of the LTPS of  FIG. 1 . 
           [0013]      FIG. 7  illustrates an enlarged detail of circle B on the right side of  FIG. 6 . 
           [0014]      FIG. 8  illustrates a cross-sectional view taken along line C-C of  FIG. 7 . 
           [0015]      FIG. 9  illustrates tap points of a single phase lateral off of phases “A” and “B” of the three phase primary for a delta connected electric power system. 
           [0016]      FIG. 10  illustrates the LTPS suspended from a pole mounted bracket for measuring current of phase A for the delta connected electric power system. 
           [0017]      FIG. 11  illustrates the LTPS suspended from phase A and phase B conductors with suspension insulators for measuring current in phase A for the delta connected electric power system. 
           [0018]      FIG. 12  illustrates a single dead ended LTPS installed on phase A for measuring current in phase A for the delta connected electric power system. 
           [0019]      FIG. 13  illustrates a double dead ended LTPS installed on phase A for measuring current in phase A for the delta connected electric power system. 
           [0020]      FIG. 14  illustrates a single dead ended LTPS installed on phase C for measuring current in phase C for wye connected electric power system. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]      FIG. 1  illustrates an example sensor transmitter receiver unit (“STR unit”)  1  attached to a low threshold current power supply (“LTPS”)  3 . The STR unit  1  includes an upper housing la and a lower housing lb. The upper housing la includes a throat T for accepting an electric power line conductors or an aluminum loop tube  2 . 
         [0022]    The STR unit  1  includes an iron core power supply transformer PST that surrounds one of the power line conductors  4  and  5  or the loop tube  2  when a pair of jaws J are clamped onto one of the power line conductors  4  and  5  or the loop tube  2 . 
         [0023]    As shown in  FIGS. 3-5 , the loop tube  2  includes five turns of insulated copper wire  6  wound inside and around the loop tube  2 . The wire  6  is wound inside the loop tube  2  through a slot  7  which extends around an outside perimeter of the loop tube  2 . Except for the top turn of the wire  6 , the four remaining turns are in intimate contact with each other and in contact with the inside wall of the loop tube  2 . Since the slot  7  is located around the outside of the loop tube  2 , a temperature of the winding of wire  6  will run cooler when current is flowing through  6  than if the loop tube  2  were enclosed. 
         [0024]    The five turns of the wire  6  are in thermal contact with each other. Heat generated by the power line conductor current I flowing through the five turns or I 2 R, R being the resistance of each turn, is conducted through a wall of the loop tube  2  and is lost by thermal convection and thermal radiation to the outside environment. Because the top turn of the wire  6  is in contact with the other  4  turns of the wire  6 , the top turn of the wire  6  not only loses its heat by conduction through the wall of the loop tube  2 , but also directly to the environment through the slot  7  by thermal convection and thermal radiation. The loop tube  2  not only acts as a form onto which the wire  6  is wound, but also becomes a convoluted fin to effectively transfer heat to the surrounding environment. 
         [0025]    In one example, the low threshold power supply  3  must be capable of carrying a maximum single phase (S) lateral current of 200 amperes per turn without exceeding the maximum temperature limit of the insulation on the wire  6 . 
         [0026]      FIG. 8  illustrates a beginning of a first turn  8  of wire  6  of the five turns. A beginning of the first turn  8  is connected to a left side connector  9  using a set screw  10 . The connector  9  is electrically connected to a left anchor rod  11 . The power line conductor  4  is electrically connected to the left anchor rod  11  using two set screws  12 . The connector  9  is held securely against the left anchor rod  11  with a threaded stud  13  which fits through a vertical centered hole in the connector  9  and is screwed into a lock block  18  on one end and is inserted in the vertical hole  19   a  of the left anchor rod  11  on the other end. 
         [0027]    The threaded stud  13  draws the lock block  18  up tight against the connector  9  and the left anchor rod  11  using a metal spacer washer  19 , a flat washer  20 , a lock washer  21 , and a nut  17 , as shown in  FIGS. 5 and 8 . The lock block  18  serves three purposes: First, the lock block  18  provides a mechanism of holding the connector  9  tight against the left anchor rod  11  using the threaded stud  13  and the nut  17 . Second, the lock block  18  includes a projection  22  on a bottom end which fits into the slot  7  and prevents the loop tube  2  from rotating. Third, the lock block  18  has two sets of horizontal holes  23  and  24  (see  FIG. 5 ) through which bolts  25  are threaded into the lock block  18  and a through bolt  26  and a nut  27  holds a band  28 . 
         [0028]    The band  28  pulls the slot  7  of the loop tube  2  up and into the projection  22  which in turn supports the loop tube  2 . An electrically conductive path exists from the power line conductor  4 , through the electrically conductive left anchor rod  11 , the electrically conductive connector  9 , and on to the beginning of the first turn  8  of the winding of wire  6 . As mentioned earlier, there are five turns of the wire  6  that surround the loop tube  2 . An end of a last turn  29  of the wire  6  terminates in a right connector  30 , which is electrically attached to a right side anchor rod  31  and the power line conductor  5 . (See  FIG. 8 ). The power line conductor  5  is held securely to the right side anchor rod  31  with two set screws  12 . 
         [0029]    The current path inside of the loop tube  2  is counterclockwise and as such the direction of the current at the bottom of the loop tube  2  is in the same direction as the path of the current in the power line conductors  4  and  5 . (See the direction arrows of current I flow in  FIG. 1 ). When the STR unit  1  is installed on the bottom of the loop tube  2 , a polarity mark  32  (see  FIG. 1 ) of the STR unit  1  must match the direction of current I coming into the polarity mark  32 . The end of the last turn  29  is inserted into the connector  30 , and a set screw  10  is tightened onto an end of the conductor  29 , as shown in  FIG. 8 . 
         [0030]    The power line current only flows through the five windings of wire  6 . None of the current is diverted through the electrically conductive loop tube  2  even though the loop tube  2  is mechanically fixed on each end using the bands  28  which are held in place by the screws  25  and through bolt  26  and nut  27  to the lock blocks  18 . 
         [0031]    In  FIGS. 7 and 8 , the lock block  18  and right side threaded stud  13  are electrically isolated from the connector  30  and right side anchor rod  31  using an electrically insulating square washer  33 , an electrically insulating sleeve  34 , and an electrically insulating washer  35 . If the loop tube  2  was not electrically insulated from the winding of wire  6  and the left and right anchor rods  11  and  31 , which are in turn connected to the power line conductors  4  and  5 , then a portion of the power line current would by-pass the winding of wire  6  and the STR unit  1  would not receive the full amount of line current times the number of turns in the winding of wire  6 . 
         [0032]    It should be noted that the beginning of the first turn  8  and the end of last turn  29  are each bent into a horizontal “U” shape. An electrically insulating bridge  36  with vertically recessed grooves  37  and  38  on opposite sides is inserted between the two vertical portions of the “U” shaped windings. The grooves  37  and  38  include a groove diameter similar to the size of the wire  6 . 
         [0033]    Once the bridge  36  is inserted between the two vertical sections of the winding of wire  6  and the grooves  37  and  38  are fully engaged with the two vertical sections, both the bridge  36  and the winding of wire  6  are wrapped with a strong insulating tape  39  (see  FIG. 2 ) to pull any slack out of the wire  6  and thus increase the rigidity of the winding of wire  6 . The purpose of the bridge  36  and the tape  39  is to hold the turns of the winding of wire  6  tightly together and to the inside of the loop tube  2 , because heavy fault currents from the power line conductors  4  and  5  of 10,000 to 20,000 amperes will create high opposing forces on the turns of the winding of wire  6 . These forces can loosen the connections at the first turn  8  at the connector  9  and at the last turn  29  at the connectors  30 , and damage the turns of the winding of wire  6  by pushing them apart. 
         [0034]    The anchor rods  11  and  31 , shown in  FIG. 8 , serve four functions: (1) To provide the same or greater line tension capability as the power line conductors  4  and  5  itself, because the power line conductors  4  and  5  are deadened mechanically on each end of the anchor rods using pins  40 ; (2) To provide the same or greater current carrying capacity as the power line conductors  4  and  5 , because the power line conductors  4  and  5  are electrically connected to the anchor rods  11  and  31  using the two sets of set screws  12  on each end of the anchor rods  11  and  31 ; (3) To physically support the loop tube  2 , the wire  6 , and the STR unit  1  through the use of the two threaded studs  13 , the lock blocks  18 , and the bands  28 ; and (4) To provide an electrical path for current from the power line conductors  4  and  5  to the connectors  9  and  30  and the wire  6 . 
         [0035]    In viewing  FIG. 8 , the two anchor rods  11  and  31  are held together with a left side threaded stud  41  and a right side threaded stud  42  and an electrically insulating spacer rod  43 . The left side threaded stud  41  is screwed into the left anchor rod  11  and into the spacer rod  43 . The right side threaded stud  42  is threaded into the right side anchor rod  31  and the spacer rod  43 . As a unit, the left and right side anchor rods  11  and  31  and the spacer rod  43  are capable of full electric power line tension. 
         [0036]    The function of the electrically insulated spacer rod  43  is to electrically isolate the left side anchor rod  11  and power line conductor  4  from the right side anchor rod  31  and the power line conductor  5 . The left and right threaded studs  41  and  42  do not touch each other inside the threaded hole of the spacer rod  43 . Therefore, the spacer rod  43  prevents any power line current from flowing through this unit of the left and right anchor rods  11 , and  31  so that all current flows through the wire  6 . 
         [0037]    The LTPS  3  is designed such that if it is desirable to remove the loop tube  2  and the wire  6 , an electrically conducting shorting bar  44  is provided as shown in  FIGS. 7 and 8 . Insertion of the shorting bar  44  in holes  45  and  46  of  FIG. 8  and tightening of the two set screws  47  and  48  (see  FIG. 2 ) onto the shorting bar  44 , creates an electrical “by-pass” path of power line current from the power line conductor  4  through left side anchor rod  11  to the right side anchor rod  31  through the shorting bar  44 . Since the shorting bar  44  is installed before the loop tube  2  is disconnected by removing the threaded studs  13 , then there is no power interruption to customers, because the load current now flows through the shorting bar  44 . 
         [0038]    The loop tube  2 , the windings of wire  6 , the connectors  9  and  30 , and the lock blocks  18  are removed as a complete assembly by removing the two threaded studs  13 . In summary, to remove a low threshold current power supply  3 , install the shorting bar  44  and remove the two nuts  17  on the threaded studs  13 . With the loop tube  2  removed, the left and right anchor rods  11  and  31 , the shorting bar  44  and spacer rod  43  can remain indefinitely on the power line conductors  4  and  5 , or until the loop tube  2  is again re-installed at this location. 
         [0039]    As mentioned earlier the pins  40  of  FIGS. 7 and 8  in the left and right anchor rods  11  and  31  are an integral part of the different installation methods for the fixed tap LTPS  3 . Although five methods will be described, these are not to be considered as the only methods of installation. One skilled in electric power utility construction may envision other variants to the installation methods outlined below. 
         [0040]      FIG. 9  illustrates a jumper J1 from the tap point on phase A of the  30  primary to the tap point on the phase A of the S lateral. The first installation method shown in  FIG. 10  bridges the jumper with the LTPS  3 . 
         [0041]      FIG. 10  illustrates a pole mounted cantilevered insulator method of installing the LTPS  3  for a delta connected electric power system. The installation method of  FIG. 10  is especially suitable for small power line conductors (such as No. 6 AWG copper) where the weight of the STR unit  1  and LTPS  3  may cause concern for old construction where the copper conductor is fully annealed. A pole mounted bracket  49  includes two horizontal spaced apart cantilevered insulators  50  and  51 , which are attached to the pole mounted bracket  49 , installed at the top of the utility pole P. Two end caps  52  and  53  on the ends of the insulators  50  and  51  have the same diameter as holes  141  of  FIG. 2  in the left and right anchor rods  11  and  31 . The holes  141  in the left and right anchor rods  11  and  31  are spaced the same distance apart as the two cantilevered insulators  50  and  51 . 
         [0042]    The LTPS  3  is installed on the two end caps  52  and  53 , which have holes drilled at the outside extremity for cotter pins. Once the LTPS  3  is in place, the cotter pins are inserted into these holes to prevent the left and right anchor rods  11  and  31  from sliding off the end caps  52  and  53 . The jumper J1 of  FIG. 9  remains in place with one end attached to phase A of the 3 primary and the other end attached to phase A of the S lateral. Therefore, there is no interruption of service to customers fed off of phase A of the S lateral. 
         [0043]    Next the power line conductor  4  of the LTPS  3  of  FIG. 10  is attached using a hotstick to phase A of the 3 primary with a hot line clamp  54  and the power line conductor  5  of the LTPS  3  is attached using a hotstick to phase A with a hot line clamp  55  to phase A of the SO lateral. The jumper J1 is then removed, and current now flows through the LTPS  3  winding of wire  6  without a service interruption. The STR unit  1  is then installed on the loop tube  2  of the LTPS  3 . Once the STR unit  1  is installed on the LTPS  3 , the current traveling through the winding of wires  6  generate power for the power supply transformer PST for the STR unit  1 . The power generated from the power supply transformer is sent to a power supply module  60  to power an onboard electronics module  63 , a transmitter/receiver  64 , and an antenna  81  (see  FIG. 1 ) and begins to transmit data. 
         [0044]      FIG. 11  illustrates a second method of installation using two suspension insulators  56  and  57  mounted on phase A and phase B of the delta connected system. Links  58  and  59  are attached to the suspension insulators  56  and  57  on one end, and the pins  40  (shown in  FIGS. 6 and 7 ) are inserted through bottom end holes of the links  58  and  59  and through the left and right anchor rods  11 , and  31 . Cotter pins are installed in holes  40   a  (see  FIGS. 5 and 7 ) in the pins  40  to hold the left and right anchor rods  11  and  31  to the links  58  and  59 . With the original jumper J1 of  FIG. 9  in place, insuring no interruption of service, the power line conductor  4  is attached to phase A of the  30  primary using a hotstick and the hot line clamp  54 . Similarly, the power line conductor  5  is attached to phase A of the S lateral using the hotstick and the hotline clamp  55 , the original jumper J1 of  FIG. 9  is then removed, and current now flows from phase A of the 3 primary to the phase A of the S lateral through the winding of wire  6  of the LTPS  3 . The STR unit  1  is then installed on the loop tube  2  of the LTPS  3  and as before transmits data. 
         [0045]      FIG. 12  illustrates a third method of installation using an automatic dead end  61  shown in  FIG. 1  on the right side of the loop tube  2  and the links  58  and  59  of  FIG. 11  on the left side for the delta connected system. The automatic dead end  61  is a commercially available product which allows the power line conductor  5  to be inserted into spring loaded jaws internal to the device upon which applying tension to the power line conductor  5  automatically grips the power line conductor. 
         [0046]    The left end of the automatic dead end  61  is formed into a “U” bracket with a hole in the end which fits onto the right side anchor rod  31  using pin  40  and cotter pin. The end of the power line conductor  5  is then inserted into the hole in the end of the right side anchor rod  31  and held electrically in contact with same using the two set screws  12  of  FIG. 8 . The left side anchor rod  11  is attached to the two links  58  and  59  using pin  40  and cotter pin, and the left ends of the links  58  and  59  are attached to a dead end insulator  62  using pin  40  and cotter pin. Here again the original jumper J1 of  FIG. 9  remains in place while the LTPS  3  is being installed. As before, the power line conductor  4  is tapped to phase A of the  30  primary using hot line clamp  54 , the original jumper J1 is removed, and then the STR unit  1  is installed using a hot stick on the loop tube  2 . 
         [0047]      FIG. 13  illustrates a fourth method of installation similar to the method shown in  FIG. 12 , except two automatic dead ends  61  are used as in  FIG. 1 . The same process of installing the automatic dead end  61  of the third method shown in  FIG. 12  is applied to both the left side anchor rod  11  and the right side anchor rod  31 . Again the original jumper J1 as shown in  FIG. 9  remains connected until the hot line clamp  54  and power line conductor  4  are installed. 
         [0048]      FIG. 14  illustrates a fifth method of installation similar to the method shown in  FIG. 12  except applied to a wye connected electric power system with the phase C current being measured on the S lateral. 
         [0049]    The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.