METREL MI 3298, Instruction Manual With Exercises

Page: 109 / 232

Power Network Application Trainer
– Earthing / Grounding network impedance measurement
109
Previous exercises describe the measurement procedure with one flex-clamp and step
by step measurement (example 2), following exercises will show procedure using one
flex-clamp but measuring of two foots together and all four foots in one step.
4.1.3.5.1 S
– Flex measuring method by using one Flex-clamp with
simulated
regular pylon’s foot condition and resistance
earth character
– measuring of two foots together
Figure 71-2: S-
Flex measurement setup for measuring two pylon foot’s
Switch position Simulated condition Application Expected result
Regular measurement place
condition (simulated resistive earth
character), flex measurement,
simulated ground wire connection
Pylons (mono and multi-leg)
with and without protective earth
cable connection
Ski lifts
Radio towers
Foot Nm. 1& 2 approx. 6,27 Ω
Foot Nm. 3 & 4 approx. 4,61 Ω
Z
tot calc
= 2,65 Ω
Table 32-2:
S-Flex measurement setup/result presentation
Measuring procedure
1. Follow the measurement setup connection described under 4.1.3.1 exercise. Connect
setup switches and ground wire accordingly. Take care that flex-clamp will be installed
around two pylon legs (around 1&2 in the first measurement and around 3&4 in the
second step).