ABB RELION 620 Series Technical Manual page 741

1MRS757644 F
4.8.2.4
620 series
Technical Manual
Operation principle
The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of DOPPDPR can be described using a module diagram. All the
modules in the diagram are explained in the next sections.
GUID-5088472A-9E14-4BF4-BDC4-3C03D661224E V1 EN
Figure 372: Functional module diagram
Power calculation
This module calculates the apparent power based on the selected voltages and
currents. The Measurement mode setting determines which voltages and currents are
used. It is also possible to use positive-sequence components for calculating the
apparent power which makes the determination of power insensitive to a possible
asymmetry in currents or voltages and corresponds to the real load on the prime mover
of the generator.
Table 699: Power calculation
Measurement mode setting
PhsA, PhsB, PhsC
Arone
Pos Seq
Table continues on next page
Protection functions
Power calculation
* *
S U I U I U
= ⋅ + + +
a a b b
P Re S
( )
=
* *
S U I U I
= ⋅ − ⋅
ab a bc c
P Re S
( )
=
*
S U I
3
= ⋅ ⋅
1 1
P Re S
( )
=
Section 4
*
I
⋅
c c
735