Setting Guidelines - ABB Relion 670 Series Applications Manual

Section 7
Current protection
Gas turbines usually do not require reverse power protection.
Figure 83
overpower protection. The underpower protection gives a higher margin and should provide
better dependability. On the other hand, the risk for unwanted operation immediately after
synchronization may be higher. One should set the underpower protection (reference angle set to
0) to trip if the active power from the generator is less than about 2%. One should set the
overpower protection (reference angle set to 180) to trip if the power flow from the network to
the generator is higher than 1%.
Underpower protection
Operate
Line
Margin
Operating point
without
turbine torque
IEC09000019 V2 EN-US
Figure 83: Reverse power protection with underpower or overpower protection
7.13.3

Setting guidelines

GlobalBaseSel : Selects the global base value group used by the function to define ( IBase ), ( VBase )
SBase ).
and (
Operation : With the parameter Operation the function can be set Enabled / Disabled .
Mode : The voltage and current used for the power measurement. The setting possibilities are
shown in table 21.
Table 21:
Set value
A, B, C
Arone
PosSeq
Table continues on next page
180
illustrates the reverse power protection with underpower protection and with
Overpower protection
Q
Operate
Line
Margin
P
Operating point
without
turbine torque
Complex power calculation
Mode
Q
P
IEC09000019-2-en.vsd
Formula used for complex power calculation
*
= × +
S V I V
A A B
EQUATION2055-ANSI V1 EN-US
*
= × -
S V I V
AB A
EQUATION2056-ANSI V1 EN-US
= × ×
S 3 V I
PosSeq PosSeq
EQUATION2057-ANSI V1 EN-US
* *
× + ×
I V I
B C C
(Equation 65)
*
×
I
BC C
(Equation 66)
*
(Equation 67)
1MRK 511 358-UUS A
SEMOD172134-4 v7
Application manual