R
1T
R
N
R
3
R
2
R
1
1
......
1
1
1
=
+
+
+
+
T
N
R
R
R
R
R
2
3
1
2
1
......
1
1
1
=
+
+
+
+
NT
N
N
R
R
R
R
R
=
+
+
+
+
- )
1
(
2
1
1
......
1
1
1
32
33
great
errors
.
Owing
to
the
same
reason
,
we
neglect
the
impact
of
mutual
resistance
and
calculate
the
equivalent
resistance
of
ground
resistance
in
parallel
from
the
general
meaning
.
Thus
,
for
ground
system
of
N
N
is
small
,
but
bigger
than
2
ground
bodies
,
we
can
list
out
N
formula
:
Of
which
,
R1
R2
.
RN
is
the
ground
resistance
of
N
ground
bodies
we
need
to
solve
.
R1T
R2T
RNT
are
respectively
the
resistance
measured
on
each
ground
branch
circuit
by
clamp
meter
.
This
is
nonlinear
equations
with
N
unknown
and
N
equations
.
It
has
certain
solution
,
but
which
is
difficult
to
solve
by
manual
operations
and
even
impossible
when
N
is
quite
big
.
Purchasing
the
limited
point
ground
system
calculating
program
software
from
our
company
,
user
shall
be
able
to
solve
it
by
using
an
of fice
computer
or
laptop
.
Principally
,
except
for
the
neglect
of
mutual
resistance
,
the
method
would
not
result
in
any
measurement
error
brought
by
neglecting
R0
.
Users
need
to
pay
attention
that
:
the
number
of
connected
ground
bodies
in
your
ground
system
shall
be
exactly
equal
to
that
of
measurement
value
for
program
calculation
and
the
program
shall
output
the
same
number
of
ground
resistance
value
.
3
Single
Point
Ground
System
From
the
test
principle
,
UNIT
series
clamp
meter
can
only
be
used
to
measure
loop
resistance
but
the
single
point
ground
.
However
,
user
can
make
a
loop
to
test
by
using
a
test
line
and
ground
polarity
near
the
ground
system
.
Two
methods
of
measuring
single
point
ground
by
clamp
meter
are
introduce
in
the
following
and
the
method
could
be
applicable
to
occasions
that
traditional
voltage
-
current
UT276A
/
278A
OPERATING
MANUAL
UT276A
/
278A
OPERATING
MANUAL
Summary of Contents for UT276A
Page 1: ...P N 110401103514 ...
Page 29: ......
