ABB REB670 Series, Applications Manual

Page: 247 / 476

100
3
2
2 3
 
UBase
U
U
EQUATION1519 V5 EN-US
(Equation 84)
where:
U2 is the maximal negative sequence voltage during normal operation conditions, plus a margin of
10...20%
UBase is the base voltage for the function according to the setting GlobalBaseSel
The setting of the current limit
3I2< is in percentage of parameter IBase. The setting of 3I2<
must be higher than the normal unbalance current that might exist in the system and can be
calculated according to equation 85 .
100
2
2 3
 
IBase
I
I
EQUATION1520 V5 EN-US
(Equation 85)
where:
I2 is the maximal negative sequence current during normal operating conditions, plus a margin of
10...20%
IBase is the base current for the function according to the setting GlobalBaseSel
11.1.3.4 Zero sequence based
M13683-43 v8
The IED setting value
3U0> is given in percentage of the base voltage UBase. The setting of
3U0> should not be set lower than the value that is calculated according to equation
86 .
100
3
0 3
0 3
 
UBase
U
U
EQUATION1521 V4 EN-US
(Equation 86)
where:
3U0 is the maximal zero sequence voltage during normal operation conditions, plus a margin of 10...20%
UBase is the base voltage for the function according to the setting GlobalBaseSel
The setting of the current limit
3I0< is done in percentage of IBase. The setting of 3I0< must
be higher than the normal unbalance current that might exist in the system. The setting can be
calculated according to equation 87 .
3 0
3 0 100
I
I
IBase
= ×
<
EQUATION2293 V3 EN-US
(Equation 87)
where:
3I0<
is the maximal zero sequence current during normal operating conditions, plus a margin of 10...20%
IBase
is the base current for the function according to the setting
GlobalBaseSel
1MRK 505 370-UEN D Section 11
Secondary system supervision
Busbar protection REB670 241
Application manual