Mastech MS2301 - Limited Point Grounding System

1
existence of so-called "mutual resistance”, R
0
is not the usual
parallel value in the sense of electrical engineering (slightly higher
than its IEC parallel output value). But because a tower-grounding
hemisphere was much smaller than the distance between the
towers, and with a great number of locations after all, R
0
is much
smaller than R
1
. Therefore, it can be justified to assume R
0
=0 from
an engineering perspective. In this way, the resistance we
measured should be R1.
Times of comparing tests in different environments and different
occasions with the traditional method proved that the above
assumption is entirely reasonable.
2. Limited Point Grounding System
This is also quite common. For example, in some towers, five
towers are linked with each other through overhead ground wire;
Besides, the grounding of some of the buildings is not an
independent grounding grid, but several grounding bodies
connected with each other through the wire.
Under such circumstances, the above R
0
regarded as 0, will yield
more error on the results of the measurement.
Due to the same reasons mentioned above, we may ignore the
impact of the mutual resistance; and the equivalent resistance of
the grounding resistance paralleled is calculated by the usual sense.
Thus, for the grounding system of N (N is smaller, but larger than 2)
grounding bodies, it can offer N equations: