User’s manual
Theory
Time domain reflectometers (
TDR
) are electronic instruments used for locating faults
in transmission lines.
A
short electrical pulse is sent over
the line, and then a reflected pulse is
observed. By knowing the delay between
two pulses, the speed of light and the
cable velocity factor, the
DTF (distance-
to-fault) is calculated. The amplitude
and the shape of the reflected pulse give
the operator idea about the nature of the
fault.
Instead of a short pulse, a “
step” function
may be sent over the cable.
32
Annex 5
TDR mode
