ABB REC650 ANSI, Technical Manual

Page: 451 / 700

Set value for
parameter
“Mode”
Formula used for complex, three-
phase power calculation
Formula used for voltage and
current magnitude calculation
Comment
8 B
*
3
B B
S V I
= × ×
EQUATION1575 V1 EN
(Equation 52)
3
B
B
V V
I I
= ×
=
EQUATION1576 V1 EN
(Equation 53)
Used when only
V
B
phase-to-
ground voltage is
available
9 C
*
3
C C
S V I
= × ×
EQUATION1577 V1 EN
(Equation 54)
3
C
C
V V
I I
= ×
=
EQUATION1578 V1 EN
(Equation 55)
Used when only
V
C
phase-to-
ground voltage is
available
* means complex conjugated value
It shall be noted that only in the first two operating modes that is, 1 & 2 the measurement
function calculates exact three-phase power. In other operating modes that is, from 3 to 9
it calculates the three-phase power under assumption that the power system is fully
symmetrical. Once the complex apparent power is calculated then the P, Q, S, & PF are
calculated in accordance with the following formulas:
Re( )
=
P S
EQUATION1403 V1 EN
(Equation 56)
Im( )
=
Q S
EQUATION1404 V1 EN
(Equation 57)
2 2 = = +
S S P Q
EQUATION1405 V1 EN
(Equation 58)
cos
P
PF
S
j
= =
EQUATION1406 V1 EN
(Equation 59)
Additionally to the power factor value the two binary output signals from the function are
provided which indicates the angular relationship between current and voltage phasors.
Binary output signal ILAG is set to one when current phasor is lagging behind voltage
phasor. Binary output signal ILEAD is set to one when current phasor is leading the
voltage phasor.
1MRK 511 287-UUS A
Section 12
Monitoring
445
Technical manual