Underground Cable Fault Distance Locator and Counter Based Damaged Cable Replacement Indicator System

Abstract

This paper deals with two objectives, the first objective focuses on finding out the location of fault occurred in any phase in the underground cable system (Clegg in Underground cable fault location. McGraw-Hill, New York, 1993) using the basic principle of Ohm’s Law. The second objective basically focussed on making a programmed counter to count the number of faults, respectively, occurring in each phase during the life span of the underground cable so that damaged cable can be replaced with a new cable of same length and characteristics after reaching the limit of predefined number of faults. For this, the concept of software counting operation (Mellor-Crummey and LeBlanc in A software instruction counter. University of Rochester, Rochester, NY, 14627) is applied on the occurrence of a short circuit fault event in any phase of the underground cable by using counter programming. For this paper, the basic concept of Ohm’s law (Paul and Kakoti in Underground cable fault locator. IARJSET 3(9), 2016) is used according to which, if a low DC voltage is applied at the feeder end through a series of resistor in cable lines, the current would vary depending upon the location of fault in the cable. A software simulation of the system consisting of an ATmega 328P microcontroller (Atmel-8271-8-bit-AVR-Microcontroller-ATmega48A-48PA-88A-88PA-168A-168PA-328-328P_datasheet_Complete, Microchip), fault sensing circuit and a low voltage regulated power supply is performed. Here, the fault sensing circuit is developed using a combination of four resistors and four switches for each phase that is an equivalent model of an underground cable line, is interfaced to an ATmega 328 microcontroller with the help of internally inbuilt ADC for providing the digital data to microcontroller.