GEK-49848A
Tabl e I bel ow l i s ts the v a ri o us model s and ran ges that a re a va i l abl e.
TABLE 1
EXTENDE D RANGE JB C RELAYS
H i -
Rel ay
Ti me
Sei smi c
I n t.
Model
Characteri sti c
U n i t
H i - Sei smi c
T i me
I ns t. C u p
Conn.
C5 1 M ( - ) A
I nvers e
No
-
2 - 1 6
1 0-80
F i g. 5
I nve rse
Yes
6 - 1 50
2 - 1 6
2 - 1 6 ' 1 0 -80
Fi g. 6
I nve rse
No
-
2 - 1 6
2 - 1 6
F i g. 7
) A
I nvers e
No
-
2 - 1 6
1 0-80
F i g. 7a
I n verse
No
-
2 - 1 6
2 - 1 6
Fi g. 7b
) A
V ery I nv.
No
-
1. 5 - 1 2
1 0-80
F i g. 5
V ery I nv.
No
-
1. 5 - 1 2
2 - 1 6
F i g. 7
B C54M ( - ) A
V ery I nv.
No
-
1.5- 12
1 0-80
F i g. 7a
) A
Extremel y I nv.
No
-
1. 5 - 1 2
1 0-80
F i g. 8
Ex tremel y I nv.
No
-
1. 5 - 12
2 - 1 6
F i g. 9
)A
Extremel y I nv.
No
-
1. 5 - 12
1 0 -80
F i g. 9a
**Al so conta1ns D C o perated a u x1l 1ary un1t.
APPLI CAT I ON
Th e Type JB C rel ays are ph ase di recti o n al o verc urrent rel ays that a re used
pri mari l y as pha s e faul t de tectors i n tran smi ss i on l i ne or feede r pro tecti ve
rel ayi ng sch emes.
Each rel ay contai ns a ti me o vercurrent u n i t and an i nstantaneous o vercurrent
u n i t that are both to rque co ntrol l ed by the i ns ta ntaneo us di rec t i o n al u n i t.
The
di recti onal un i t i s quadrat ure pol ari zed; i .e., the 11a11 pha s e rel ay u s es 11a11 pha s e
c urrent and "b-e" vol ta ge, etc. The angl e of ma xi mum to rque of the di recti onal uni t
i s a ppro xi matel y 45 de gree s; i .e., maxi mum to rque wi
11
occ u r for rel ay cu rrent
l aggi ng the u ni ty powe r fa ctor pos i tion by 45 degrees, o r con ve rs el y, l ea di ng the
quadrat ure vol tage by 45 de grees.
It i s somet i mes the practi ce to use two JB C type pha s e rel ays and a di recti onal
gro und rel ay such as the IBCG to i mpl ement the prote cti ve rel ayi ng s c h eme. Where
s uch prac ti ce i s fol l owed, the pha s e from whi ch the pha s e rel ay i s el i mi nated mus t
be the s ame througho ut the sys tem; otherwi se protecti on mi ght not be pro v i ded fo r
al l faul t conti ngenci es.
The di fferences between the vari ous model s co vered by thi s i nstructi on book a re
s hown i n Tabl e 1. I n ve rse ti me rel ays s ho ul d be used on systems where the fa ul t
cu rrent fl owi ng through a gi ven rel ay i s i n fl uen ced l argel y by the sys tem generati ng
ca pa ci ty at the ti me of the fa ul t.
Very i n verse ti me and extremel y i n verse ti me
rel ays s ho ul d be u s ed i n cases whe re the faul t current magn i tude i s de pendent ma i nl y
u pon the l o cati on of the fa ul t i n rel ati on to the rel ay, and o nl y sl i ghtl y o r not at
4
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