Operation; Principles Of Operation; Accuracy And Velocity Of Propagation (Vp) - AEMC CA7027 User Manual

4.1
The Fault Mapper Pro
to travel to the far end of the cable under test, or to an intermediate
fault and return. The velocity at which the signal travels Vp (Velocity of
Propagation) will depend on the characteristics of the cable.
Based on the selected Vp and the measured travel time of the test pulse,
the Fault Mapper Pro
their distances along the cable.
4.2
The Fault Mapper Pro
to an accuracy of ±1%. This measurement accuracy is based upon the
correct value of Vp being used for the cable under test, and homogeneity
of the Vp along the cable length.
If the Vp is set incorrectly by the operator, or the Vp varies along the
length of the cable, then additional errors will be incurred and the
measurement accuracy will be affected.
See § 4.8 for setting the Vp.
Correct measurement of fault distances is also dependent on the cursor
being positioned accurately by the operator. When locating faults with the
Fault Mapper Pro
feature on the cable waveform as shown below.
8
1.800.561.8187

Principles of Operation

®
works by measuring the time taken for a signal
® calculates and displays impedance anomalies and

Accuracy and Velocity of Propagation (Vp)

®
measures distances to faults and cable lengths
NOTE: The Vp is less well defined with unshielded multi-conductor cable,
including power cable, and is lower when a cable is tightly wound on a
drum than when it is installed in a linear fashion.
®
the cursor should be positioned at the beginning of the
Vp=72% Z=100Ω
621ft
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CHAPTER 4

OPERATION

Fault Mapper Pro
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®
Model CA7027
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