ABB REL300 Instruction Manual page 146

I.L. 40-385.7
where
(3I is zero sequence fault current.)
OF
(T
MSEC
T
MSEC
For values of 3I
(T
MSEC
The following equation can be used to calculate the trip time for all CO curves from CO-2 to
CO-11:
T(sec)
T(sec)
where
GBPU
GTC
T , K, C, P and R are constants, and are shown in Table A-2.
o
Step 24.
• +72°
• -15° (± 87°)
• -102°
The relay should not trip at the angles of:
• +78°
A-12
3I
OF
I = ---------------
0
GBPU
4122
478 +
----------------------------- -
) =
4.1/0.5 -1.27
= 1073 msec
1.073 sec ± 5 % to trip
=
between 1.0 and 1.5, the following equation would apply:
0
( )
9200 GTC
×
---------------- - ----------- -
) =
3I – 1 24
0
= T +
------------------------- -
0 (
3I
R
= --------------------- -
( )
3I – 1
0
3I
OF
I = ---------------- -
0
GBPU
= Pickup current setting (0.5 to 4.0A).
= Time curve dial setting (1 to 63).
For a Zero Sequence Directional unit (DIRU = ZSEQ), the tripping direction of
REL300 is: the angle of 3I
of GDIR to "YES". Apply AG fault as shown in preceding Step 10, Figure B-1. The
relay should trip at the following angles:
24
----- -
24
( )
CO 8 only –
GTC
K
× (
----------------- - for 3I
,
)
p 24 000
– C
0
GTC
× ( < <
----------------- - for 1 3I
,
0
24 000
leads 3V between +75° and +255°. Change the setting
0 0
≥ )
1.5
0
)
1.5