MTE PTS 400.3 PLUS - Page 152

PTS 400.3 PLUS Operation Manual_R02 Page 152/306
Burden factor
Ratio of real part (R) to impedance (Z). The value is calculated based on
the measured values U and I.
Burden factor
Phase angle of burden
Z
R
cos =






=






=
−−
R
X
tan
Z
R
cos
11
Rated operating burden
Burden related to the rated current, calculated with the measured imped-
ance (Z) and the entered rated current (IN). This value can directly be
compared with the rated burden specified by the manufacturer (SN). Be-
cause the calculation of SN is based on the impedance (Z), the measure-
ment is independent of the actual secondary current (I). The secondary
current (I) can be different from the rated value (IN). The result remains the
same.
Rated operating burden
I
U
INZINSn
22
==
Total rated operating burden
Resistance of wire and junctions
Burden related to the rated current with regard of voltage drops between
secondary connections of the current transformer and the measuring point
of the burden voltage (U).
The voltage drop is calculated with the optional entries for length (l) of wire
from measuring point to transformer and back and cross section (A) of the
wire.
Total rated operating burden
Resistance of wire
( )
RlZINSn
2
+=
A
l
Rl =
If A and l are zero: Sn = Sn
Resistance (real part of Z)
Reactance (imaginary part of Z)
Impedance Z
The impedance (Z) and its real part (R) and imaginary part (jX) are calcu-
lated based on the measured values U and I.
Impedance
Complex Impedance
22
XR
I
U
Z +==
jXR
I
U
Z +==
Assign results to phase L1, L2, L3
Select L1, L2, L3 to assign the measured results (U1, I1) to the corresponding phase (cy-
clical mode).
The calculated results are indicated with the index of the selected phase. This function
can be used to test a 3 phase meter phase by phase and save the results.