ABB Relion 670 series - Principle of operation

7.11.2 Principle of operation
A simplified scheme showing the principle of the power protection function is shown
in figure 239. The function has two stages with individual settings.
Chosen current
phasors
Chosen voltage
phasors
Complex
power
calculation
P
Derivation of
S( composant)
in Char angle
S( angle)
S( angle) <
Power1
t TRIP 1
PICKUP1
Q
P = POWRE
Q = POWIM
S( angle) <
Power2
TRIP2
PICKUP2
0
t
0
ANSI06000438-2-en.vsd
ANSI06000438 V2 EN
Figure 239: Simplified logic diagram of the power protection function
The function will use voltage and current phasors calculated in the pre-processing
blocks. The apparent complex power is calculated according to chosen formula as
shown in table
233.
Table 233: Complex power calculation
Set value:
Mode Formula used for complex power calculation
A, B, C
* * *
A A B B C C
S V I V I V I= × + × + ×
EQUATION2055-ANSI V1 EN (Equation 97)
Arone
* *
AB A BC C
S V I V I= × - ×
EQUATION2056-ANSI V1 EN (Equation 98)
PosSeq
*
3
PosSeq PosSeq
S V I= × ×
EQUATION2057-ANSI V1 EN (Equation 99)
AB
* *
( )
AB A B
S V I I= × -
EQUATION2058-ANSI V1 EN (Equation 100)
Table continues on next page
Section 7 1MRK505222-UUS C
Current protection
472
Technical reference manual