METREL MI 3298, Instruction Manual With Exercises

Page: 63 / 232

Power Network Application Trainer
– Earthing / Grounding network impedance measurement
63
Figure 44-2: Substitute circuit for Passive (Flex Clamps) measurement
Notes:

Inductive current I
gw
flows into earth through Z
sel1/1
, Z
sel2/1
, Z
sel1/2
and Z
sel2/2

The voltage drop is measured by auxiliary potential probe (S).

The selective currents I
f1-4
is measured through the earthing electrode Zsel
1-4/1
(pylon foots) selected by the user.

The selected earth impedance Z
sel1-4/1
is determined from the voltage U
S
–E
and
selected current (external current clamp
– I
f1-4
) ratio.

When using only one, two or three flex clamps, always connect one clamp to F1
terminal (synchronization port).

Make sure that the arrow marked on the clamp coupling points toward the correct
orientation for correct phase measurement.

Make sure that the number of turns is correctly entered in the test parameters
window