ABB Relion Technical Manual page 539

1MRK 502 048-UUS A
Technical manual
Set value for Formula used for complex, three-
parameter phase power calculation
"Mode"
8 B
= ×
S 3
EQUATION1575 V1 EN
9 C
= ×
S 3
EQUATION1577 V1 EN
* 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:
=
P Re( ) S
EQUATION1403 V1 EN
=
Q Im( ) S
EQUATION1404 V1 EN
= = 2 + 2
S S P Q
EQUATION1405 V1 EN
P
j
= =
PF cos
S
EQUATION1406 V1 EN
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.
Formula used for voltage and
current magnitude calculation
× V
*
V I
B B
(Equation 107)
=
I
EQUATION1576 V1 EN
× * V
V I
C C
(Equation 109)
=
I
EQUATION1578 V1 EN
Section 14
Monitoring
Comment
Used when only
= × V
3 V
B
B ground voltage is
available
I
B
(Equation 108)
Used when only
= × V
3 V
C
C
ground voltage is
available
I
C
(Equation 110)
phase-to-
phase-to-
(Equation 111)
(Equation 112)
(Equation 113)
(Equation 114)
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