GEK-49849
G ROUND
DIR ECTIONAL
O V ERCURR ENT
R ELAYS
G R O UN D DIR ECTIO N AL O V E R C U R R E N T R EL A YS
TYP ES:
JBCG51M
JBCG52M
JBCG5 1M (- ) Y 1A
JBCG5 3 M
JBCG5 4 M
JBCG5 3 M (- ) Y lA
JBCG7 7 M
JBCG7 8M
D ESCRIPTION
The Type JBCG relays are groun d d i rect i onal overcurrent relays that are used
pr i mar i ly for the protect i on of feeders and transmi ss i on li nes . They are avai lable
wi th i nverse, very i nverse, or extremely i nverse t i me char acteri st i cs .
All the JBCG relays contai n a t i me overcurrent uni t of the i nduct i on d i sk type,
an i nstantaneous overcurrent cup type un i t, and an i nst antaneous d i rect i onal cup
type un i t .
The d i rect i onal un i t can be potent i al polar i zed, current polar i zed, or
both, and i t d i rect i on ally controls the oper at i on of both the t i me overcurrent d i sk
un i t and the i nstantaneous cup uni t .
Those relays h avi ng the des i gn at i on YlA followi ng the model number also cont a i n
a H i - Se i smi c i nstantaneous un i t of h i nged armature construct i o n .
Th i s un i t i s non
d i rect i onal and h as a self-contai ned hand reset t arget that wi ll show whenever the
uni t h as oper ate d .
Two target sea
1-
i n uni ts are provi ded i n each o f the relays.
T h e operat i ng
coi l of e ach of these uni ts respect i vely i s connected i n seri es wi th the cont acts of
the t i me overcurrent un i t and the i nstan taneous overcurrent uni t . The cont acts of
each seal- i n un i t respect i vely are connected i n par allel wi th the contacts of the
t i me over current uni t and the i nstantaneous overcurrent un i t to pro vi de protect i on
for them and the associated control spr i n g .
All the JBCG relays are mounted i n standard L2 s i ze drawout cases; t h e outli ne
and panel dri lli ng d i me n s i ons for wh i ch are shown i n F i g. 25 .
I nternal connect i on s
for t h e relays are shown i n F i g . 5, 6 a n d 7 . Typ i cal external connect i ons are shown
by F i g .
8 and 9. The JBCG52, JBCG54 and the JBCG7 8 are daub
1
e contact re
1
ays of
the 51, 53 and 77 models . The i nternal connect i on d i agrams are shown i n F i g . 26 and
27 .
These instructions do not purport to cover all details or variations in equipment nor to provide for
every possible contingency to be met in connection with installation,
operation or maintenance.
Should
further information be desired or sho uld particular problems arise which are not covered sufficiently for
the purchaser's purposes, the matter should be referred to the General Electric Company.
To the extent required the products described herein meet applicable ANSI,
IEEE and
NEMA
standards;
but no such assurance is given with respect to local codes and ordinances because they vary greatly.
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