Time - Domain Reflectometry Hardware Design And Implementation,

Power cable fault occurs regularly in power system. Fault location is the precondition to eliminate the fault. Accurate fault location can shorten the time to find out the fault point, eliminate cable fault quickly and reduce the cost that the power cable fault had produced.Based on the digital storage oscilloscope technology and the theory of transmission line, this project designs a utility-type and multi-function time-domain reflectometer (TDR) utilizing the principle that electric signal's transmission and reflection on cable at the time-domain point of view. Through the measurement of time interval between emission pulse and reflection pulse, the TDR realize the fault location and judgment, the measure-definition less-than 0.5m.This paper detailed introduces the overall design of hardware to the TDR. Through the clock count to generate pulse whose width can modified, and make the pulse ordinal delay use the principle of vernier caliper. The amplified pulse signal had respective sent to measurement channel and reference channel. The emission pulse and reflection pulse get into high-speed data sampling system after conditioning by analog channel, then processor display the pulse waveform and test result on the LCD. Through the subtration operation of the two waveform can make the range hole less than 1m. This paper also design the portable power circuit and hardware and software switch circuit. At last the test and validation are completed according to the design demand, and show the picture of actual experiment. The measuring result reveals that the design satisfies the preconcerted require and technical assurance for industrialization.