4.24
SEL-734 Meter
Instruction Manual
Date Code 20090730
Metering
Transformer/Line Loss Compensation
Transformer Losses
Three-phase transformer loss calculations are shown in
–
. For three single-phase transformer applications,
%Z, %IMAG, LWCU, and LWFE must be averaged.
The designator “B” will follow all primary (user-defined) values to distinguish
them from secondary (internal metered) values.
Equation 4.6
Equation 4.7
Equation 4.8
Equation 4.9
Where:
Equation 4.10
Equation 4.11
Equation 4.12
Equation 4.13
Equation 4.14
Equation 4.15
LVCU = copper (load) VAR loss, at rated current
LVFE = iron (no-load) VAR loss, at rated voltage
Line Losses
The impedance of power carrying conductors causes line losses. The resistive
component causes active power losses (watts) while the reactive component
causes reactive power (VAR) losses. If the conductor resistance and reactance
Line Losses
SLR
Supply line resistance in ohms primary
SLX
Supply line reactance in ohms primary
LLR
Load line resistance in ohms primary
LLX
Load line reactance in ohms primary
XFTR
Power transformer turns ratio
Table 4.12
Required User Input
(Sheet 2 of 2)
V
Supply
V
Load
--------------------
LWCU
LWCUB
I
DICF
•
(
)
2
•
=
LWFE
LWFEB
V
DVCF
•
(
)
2
•
=
LVCU
LVCUB
I
DICF
•
(
)
2
•
=
LVFE
LVFEB
V
DVCF
•
(
)
4
•
=
DICF
3
KVLL
•
MVA
1000
•
---------------------------------
=
DVCF
3
KVLL
-----------------
=
LVCUB
VACUB
2
LWCUB
2
–
=
LVFEB
VAFEB
2
LWFEB
2
–
=
VAFEB
%IMAG
100
----------------------
MVA
•
=
VACUB
%Z
100
---------
MVA
•
=
Содержание SEL-734
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