METREL MI 3298, Instruction Manual With Exercises

Page: 125 / 232

Power Network Application Trainer
– Earthing / Grounding network impedance measurement
125
4.1.6.2 Auto Sequence procedure - 4-Pole/ HF measuring method / S-
Flex
– broken earth connection with simulated GW connection
Figure 79-2:
4-pole, HF and S-Flex measurement setup
Switch position Simulated condition Application Expected result
Simulated broken foot Nm. 2 & 3
connection (simulated inductive
earth character), simulated ground
wire connection
Pylons (mono and multi-leg)
with and without protective earth
cable connection
Ski lifts
Radio towers
4-pole:
Ze = 1,78
Ω @ 329 Hz
HF:
Re = 6,7
Ω @ 25kHz
S-Flex:
Foot Nm. 1 approx. 14,76 Ω @ 329 Hz
Foot Nm. 2 approx. 348 Ω @ 329 Hz
Foot Nm. 3 approx. 1,767 kΩ@ 329 Hz
Foot Nm. 4 approx. 6,62 Ω @ 329 Hz
Z
tot calc
= 4,49
Ω
Table 41-2: 4-pole, HF and S-Flex setup/result presentation
Three measurement methods (4-pole, HF
– 25 kHz and S-Flex method) executed under
single Auto Sequence will be used under same test object for comparing the results and
executed with single press on “Start” button.
To join three measuring methods under single Auto Sequence, we need to prepare
appropriate one and connect the measured object properly, to be ready for all selected
measurement methods.