Electric Power Research Institute Incorporated

Lucent Technologies Inc.

Jack F Trezza

Michael H Silverberg

Garrett S Sylvester

John F Rossi

David Robert Smith

Thomas M Sperlazzo

A method of pinpointing the location between manholes of a fault in an electrical cable typically buried underground in an urban environment, the fault being caused by an insulation defect which may be broken down by a high voltage includes the steps of applying the voltage to break down the fault insulation defect to induce a transient fault pulse on the cable on both sides of the fault traveling away from the fault. By the use of a ferrite type transformer coupler producing an output voltage, the direction of the transient fault pulse is determined by relating the polarity of the output voltage to the initial high voltage pulse which was applied.

Method of locating a fault in an electric power cable

There is provided a system and method for locating faults in power distribution systems with complex topology, such as multi-phase urban networks (6), utilizing reliable time-delay techniques as well as a transponder (22) at a monitoring point to sense the arrival of the transient fault pulse and for transmitting a timing pulse a known time delay after sensing the arrival of the transient fault pulse and a calibration pulse a known time delay after transmitting the timing pulse. Installed along the power distribution system at key locations are receiver stations (4, 4a, 4b) capable of sensing the arrival of the transient fault pulse, timing pulse and calibration pulse and measuring the time intervals occurring between each. The location of the fault is then determined based on these timing intervals, known time delays and the known propagation velocity of the electric power cables in the power distribution system. Fault location accuracy is further enhanced by factoring rise-time effects of the sensed pulses into the time interval measurements.

System and method for locating faults in electric power cables

Apparatus for identifying faults within electrical power cables is provided. The apparatus allows a user to detect faults in cables regardless of the cable environment's noise content. Circuitry may be included for filtering the received test signal based on an understanding of a generic urban noise environment. The apparatus can provide the user with the size and direction of the test signal at a particular testing location.

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Hopatcong, NJ, United States of America

Jack F Trezza