Megger Digiflex Com - Page 55

man_digiflex_com_en_02_5.doc 55
v
/
2
In cable testing it is common practice to specify the signal
propagation velocity in term of half the actual velocity. When
employing the reflection technique, this is a usual way of
taking twice the signal travel path into account. To depict a
reflection on the screen, the signal has to travel from the
meter to the fault and back. If the
v
/
2
values of various
cables are listed in a table, these values can directly be
used to convert the measured signal propagation time t
x
into
fault distance E.
EQ E = \F(v,2) · t
x
Reduction Factor
(
german ”Verkürzungsfaktor”)
 NVP (Nominal Velocity (of) Propagation)