Leakage current sensor for suspension type insulator

Abstract

A sensor apparatus for detecting leakage current in a suspension-type insulator of an electrical power system includes: a housing having a first half of a leakage current sensor contained therein; a door pivotally connected to the housing by a hinge, and having a second half of the leakage current sensor contained therein, the door pivotable about the hinge between an open position in which the first and second halves of the leakage current sensor are separate from each other, and a closed position in which mating surfaces of the first and second halves of the leakage current sensor join together to define a closed perimeter; and a clamping mechanism connected to the housing comprising a first jaw and a second jaw, wherein the jaws are moveable between an open position and a closed position.

What is claimed is: 
     
         1 . A sensor apparatus for detecting leakage current in a suspension-type insulator of an electrical power system, the apparatus comprising:
 a housing having a first half of a leakage current sensor contained therein;   a door pivotally connected to the housing by a hinge, and having a second half of a leakage current sensor contained therein, the door pivotable about the hinge between an open position in which the first and second halves of the leakage current sensor are separate from each other, and a closed position in which mating surfaces of the first and second halves of the leakage current sensor join together to define a closed perimeter and;   a clamping mechanism connected to the housing comprising a first jaw and a second jaw, wherein the jaws are moveable between an open position and a closed position.   
     
     
         2 . The apparatus according to  claim 1 , wherein:
 the first jaw is supported by a first arm;   the second jaw is supported by a second arm;   a first threaded collar is connected to the first arm;   a second threaded collar is connected to the second arm; and   a bolt mechanism is disposed in threaded engagement with the first and second arms.   
     
     
         3 . The apparatus according to  claim 2 , wherein the bolt mechanism includes first and second opposing bolts coupled together at their ends by a coupling. 
     
     
         4 . The apparatus according to  claim 2 , wherein the first and second jaws include a plurality of apertures for receiving a fastener therethrough. 
     
     
         5 . The apparatus according to  claim 1 , further including a hot stick adapter mounted to the housing. 
     
     
         6 . The apparatus according to  claim 1 , further including a fastener for securing the door in the closed position. 
     
     
         7 . The apparatus according to  claim 1 , further including an electronics module configured to receive a signal from the leakage current sensor and a communications system operable to wirelessly transmit the signal to an external receiver. 
     
     
         8 . The apparatus according to  claim 1 , wherein the leakage current sensor is operable to generate an analog signal proportional to a received leakage current. 
     
     
         9 . The apparatus according to  claim 1 , wherein the leakage current sensor includes a current transformer having:
 a ferrite core having windings wrapped therearound; and   a metal housing around the ferrite core and windings to shield the current transformer from magnetic fields, wherein the metal housing includes a slot extending along an inner surface thereof.   
     
     
         10 . A method of detecting leakage current in a suspension-type insulator of an electrical power system, the method comprising:
 installing a grounded end fitting of the insulator in the apparatus of  claim 7 ;   conducting a leakage current from a grounded end fitting of the insulator through a current transformer of the leakage current sensor;   generating an analog signal proportional to the leakage current flowing through the current transformer;   using the electronics module to receive the analog signal and convert the analog signal to a digital value; and   using the communications system to wirelessly transmit the digital value to an external receiver.   
     
     
         11 . The method according to  claim 10 , further including the step of using the electronics module to assign the digital value to one of a plurality of bins based on a magnitude of the digital value, wherein each of the plurality of bins represents a predetermined range of magnitudes of leakage current. 
     
     
         12 . The method according to  claim 11 , further including the step of incrementing the assigned bin each time a digital value is assigned to the bin. 
     
     
         13 . The method according to  claim 10 , further including the step of using the electronics module to detect a peak value of the analog signal at a first interval. 
     
     
         14 . The method according to  claim 13 , further including the step of using the electronics module to convert the peak value to the digital value. 
     
     
         15 . The method according to  claim 10 , wherein the step of installing the grounded end fitting includes the steps of:
 moving the door of the apparatus to an open position;   moving the jaws to an open position;   receiving the grounded end fitting between the jaws and moving the jaws to the closed position, such that the jaws clamp onto the grounded end fitting and secure the sensor apparatus to the insulator; and   moving the door to the closed position and securing the door in the closed position.