Zero Sequence Based; Delta U And Delta I - ABB REQ650 Applications Manual

1MRK 505 291-UEN A
9.2.3.4
9.2.3.5
Application manual
3 2 I
< ×
3 2 I 100
=
IBase
EQUATION1520 V3 EN
where:
3I2 is the maximal negative sequence current during normal operating conditions, plus a margin of
10...20%
IBase
is the setting of base current for the function

Zero sequence based

The relay setting value 3U0> is given in percentage of the global parameter UBase.
The setting of 3U0> should not be set lower than according to equation 74.
3 0 U
>= ×
3 0 U 100
UBase
EQUATION1521 V2 EN
where:
3U0 is the maximal zero sequence voltage during normal operation conditions, plus a margin of
10...20%
UBase is setting of global base voltage all functions in the IED.
The setting of the current limit 3I0< is done in percentage of the global parameter
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 75.
3 0 I
<
3 0 I 100
= ×
IBase
EQUATION2293 V2 EN
where:
3I0<
is the maximal zero sequence current during normal operating conditions, plus a margin of
10...20%
IBase
is setting of global base current all functions in the IED.

Delta U and delta I

Set the operation mode selector OpDUDI to On if the delta function shall be in
operation.
The setting of DU> should be set high (approximately 60% of UBase) and the current
threshold DI< low (approximately 10% of IBase) to avoid unwanted operation due to
Secondary system supervision
Section 9
(Equation 73)
(Equation 74)
(Equation 75)
177