Ge N E Ra L - GE SBC23A Instructions Manual

t h e current de tecto rs a re s e t to p i ck up bel ow l oa d c u r r e n t ma gn i tudes.
mo s t, i f n o t al l , s t a t i c l i ne re l ayi n g sys tems i ncl u d e t he i r own s e a l - i n fu nct i o ns.
T h u s, the B FI fu nct i on i l l u s t ra ted on the sta t i c l i n e rel ay l o g i c d i a grams w i l l
prov i de a co n t i n u o u s i npu t.
The el ectr i cal l y-sepa ra te
rece i ves an i nput from t h e
d etecto r ope ra tes.
trip s i gnal to t h e breaker w i th wh i ch the SB C is a s soci a ted, the reby i nc re a s i n g the
o v e ra l l secu r i ty o f t h e sch eme.
a s soci a ted breaker wo u l d a l ready have rece i v ed a tr i p s i g n a l
rel ayi n g. Thus t h e sepa ra te t r i p s i gnal prov i d es a n a l te rnate chance to t r i p the
breaker co r rectl y, i n the even t of some fa i l u re i n the pro tect i v e rel ay t r i pp i ng
ci rcu i t s, the reby avo i d i n g u n n ece s s a ry t r i pp i n g o f t h e backup bre ake rs.
Fu rthe rmo re, th i s fea t u re i ncrea s e s s ecu r i ty du r i n g test i n g, s i nce a m i s take i n te s t
proce d u res t h a t r e s u l ts i n i n i t i a t i n g t h e S B C ope ra t i o n w i l l cau se t h e tr i pp i n g o f
o n l y t h e o n e breaker a s soci a ted w i th
a s soci a ted breake r
de tecto r s w i l l re s e t, t h u s prev en t i n g the S B C from t i mi n g o u t.
In the S B C 2 3 B a nd
i n terna l l y to s t ud l l A, i n s tead o f s tud 9 as i n the SBC23A.
i s re qu i red, s tud l l A mu s t b e i n t e rna l l y jumpe red to s tu d 11, a nd s t u d 11 exte rnal l y
co n n ected to ( + ) DC.
i n stantaneous tr i pp i n g, w i th the re s tr i ct i on t h a t s tu d 11 i s co n n ected to ( + ) DC.
OPERATION - GENERAL
There a re fou r curre n t i npu ts to
cu r ren ts ( I A , Is , Ic ) and g ro u nd
appl i ca t i on of the B FT co n tacts d epend upo n t h e bu s a n d breake r a rra n geme n t, a s
prev i o u s l y expl a i n ed.
6 2Y ) act i v a te s t h e powe r s uppl y.
on t he a s soci a ted l i ne.
fau l t a nd a re produci n g a t r i p o u tput.
faul t d i sappea rs and
e l ectromech a n i cal
e l ectromech an i ca l rel ays prod uce a tr i p s i gna l t o tr i p t h e a s soci a ted breaker.
When t h e powe r s uppl y i s ac t i v a ted, t h e cu r re n t- l evel
ou tpu t i f the cu r rent i n th e a s soci a ted breake r i s abo v e the l e v e l - de tector s e tt i n g.
The o u tput o f t h e l evel
s e l ected by pl aci n g the l o g i c tap i n 11 LD1 1 ( Level De tecto r ) po s i t i on.
t i me ( A) of t h e A/0 t i mer, a s prev i ou s l y d escr i be d, wou l d be s e t l o ng enoug h to g i ve
t h e p r i ma ry breake r a cha nce to tr i p cor rectl y, b u t s h o rt e n o u g h to e n s u re sys tem
s tabi l i ty i n the e v e n t t h a t t h e p r i ma ry breake r s ho u l d fa i l to t r i p.
Wh en t i mer A/0 t i me s o u t, i t ene r g i ze s tran s i s to r sw i tch ( TS ) , w h i ch i n tu rn p i cks
up the B FT u n i t, the co n tact s o f wh i ch i n i t i a te t r i pp i n g of the n ecessa ry backup
breake rs. If the pri ma ry breaker cl e a r s the faul t correctl y, e i t h e r t h e i n i t i a t i n g
co n tact ( B FI, 6 2X o r 6 2 Y ) o r t h e l evel d e tecto r w i l l h ave r e s e t be fo re t h e A/0 t i me r
t i mes o u t, a nd n o tr i pp i n g o f t h e back up b reaker w i l l occu r.
GEK-45464
co n tact prov i d es a n o u tput a s soon a s t h e S B C
( IT I )
i n i t i a t i n g con tacts
Th i s o u tpu t con tact ca n be u s ed to appl y a sepa ra te, i nd epend ent
Und e r u s u a l ope ra t i n g co nd i t i on s o f t h e S B C, the
i s tr i pped by th i s
S B C 2 3 C rel ays,
The IT! con tact be tween s tuds 11 a nd 12 can s t i l l be u sed fo r
the S B C2 3 rel ays.
current ( 3I o ) .
T h e ope ra t i on be g i n s w h e n t h e contact i n i t i a t i on ( B FI, 6 2X,
The B FI con tacts woul d come from the s ta t i c rel ays
Th e s e co n tacts w i l l cl o s e when the sta t i c rel ays see a
the rel ays re s e t.
l i ne rel ays, and
d e tecto r e n e rg i ze s t h e A/0 t i me r a nd the IT u n i t,
( B FI,
t h e S B C. Th i s
add i t i on a l co n tact
t h e n o n - i s o l a ted IT 2
T h e co n tact i n i t i a t i o n a nd the
The B FI co n tacts w i l l s tay cl o se d u n t i l the
The 6 2X a n d
these co n tacts w i l l
7
Note that
6 2X, 6 2 Y ) a nd t h e l evel
from the pro tect i v e
i s s o beca u s e when
o u tput, t h e
co n tact i s co nnected
I f the s e a l - i n fu nct i o n
They a re th e th ree phase
62Y con tacts come
cl o s e wheneve r
d e tecto r w i l l prod u ce a n
The opera t i ng
the
cu rre n t
from
t h e
i f