On-line time domain reflectometer system

Abstract

A number of TDR systems and testing methods are provided that improve the quality and accuracy of information collected when propagating a signal along a length of cable in order to pinpoint specific anomalies. One or more of the TDR systems includes, for example, a computing device, a pulse generator, and at least one capacitive test sensor. The at least one capacitive test sensor transmits/receives pulses to/from a power system component, such as an insulated power cable, in a capacitive manner.

The embodiments of the disclosure in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A method of testing a power system component for anomalies, comprising:
 capacitively coupling one or more test sensors to an on-line insulated medium voltage power transmission cable;   generating a test pulse via a pulse generator having an output impedance greater than 500 ohms;   transmitting the test pulse to at least one test sensor of the one or more test sensors;   capacitively transmitting the test pulse from the at least one test sensor of the one or more test sensors onto the medium voltage insulated power cable so that the test pulse travels along the medium voltage insulated power cable; and   capacitively receiving a reflected pulse by one test sensor of the one or more test sensors from the medium voltage insulated power cable, the reflected pulse resulting from the test pulse interfacing with an anomaly along the medium voltage insulated power cable.   
     
     
         2 . The method of  claim 1 , further comprising:
 displaying the reflected pulse on a display in a time domain.   
     
     
         3 . The method of  claim 1 , further comprising:
 amplifying the received reflected pulse with an amplifier having an input impedance of greater than 500 ohms.   
     
     
         4 . The method of  claim 1 , wherein said generating a test pulse via a pulse generator having an output impedance greater than 500 ohms includes
 generating a test pulse via a pulse generator having an output impedance greater than 1000 ohms.   
     
     
         5 . The method of  claim 1 , wherein said capacitively coupling one or more test sensors includes capacitively coupling a first test sensor to the on-line insulated medium voltage power transmission cable for receiving the test pulse from the pulse generator and capacitively transmitting the test pulse to the insulated medium voltage power transmission cable and capacitively coupling a second test sensor to the on-line insulated medium voltage power transmission cable for capacitively receiving the reflected pulse. 
     
     
         6 . The method of  claim 1 , wherein said capacitively coupling one or more test sensors to an on-line insulated medium voltage power transmission cable includes capacitively coupling one or more test sensors to an on-line insulated medium voltage power transmission cable carrying at least medium voltage power. 
     
     
         7 . A method of testing a power system component for anomalies, comprising:
 connecting, in electrical communication, a pulse transmission line with a test sensor housed in a medium voltage power cable termination elbow;   generating a test pulse and transmitting the test pulse to the test sensor via the pulse transmission line;   capacitively transmitting the test pulse from the test sensor onto a medium voltage power cable coupled to the medium voltage power cable termination elbow so that the test pulse travels along the medium voltage power cable; and   capacitively receiving a reflected pulse by the test sensor from the medium voltage power cable, the reflected pulse resulting from the test pulse interfacing with an anomaly along the medium voltage power cable or an electronic component connected to the medium voltage power cable.   
     
     
         8 . A time domain reflectometry system, comprising:
 an on-line dielectrically insulated medium voltage power transmission cable configured to carry medium voltage power;   a transmit circuit including a pulse generator configured to generate a pulse, the transmit circuit configured to capacitively impart the pulse onto the medium voltage power transmission cable; and   a receive circuit configured to capacitively receive a reflected pulse from the medium voltage power transmission cable.   
     
     
         9 . The time domain reflectometry system of  claim 8 , wherein the on-line dielectrically insulated medium voltage power transmission cable is an underground on-line dielectrically insulated medium voltage power transmission cable. 
     
     
         10 . The time domain reflectometry system of  claim 8 , wherein the drive circuit and the receive circuit are configured to have an impedance of greater than 500 ohms.