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CARiliER RELAYING
NEG.
CARRIER
RECEIVER
BELL
Fig. 3-Time Delay Circuit For the Carrier Alarm When Using
the Carrier Channel For Telemetering or Supervisory.
The Type s
HRK
o r
HRP ground re lays have a
e lement
dire c t i onal
ove r -current e lement s .
e lement s i s exp l ained be l ow .
The s chemat i c
carrie r cont r o l and t rip c i r
cuit s are shown
s imp l ified
Type
or
re lay shown here
HZM
HZ
third
impedance e l ement
i onal
c ont r o l of the
a l s o c an be u sed with the o lde r type HZ re lays
with
two make and
one b reak
e lement c ontact s .
With
relay
the carri e r
c ont r o l
s chemat i c a l ly i n Figure 2 .
cu s s ion
re fers
direct ly
p l i e s e qua l l y we l l t o Figure
cuit s u s ing e ither type HZ re lay are basically
the same
a s shown in
r i e r i s c oncerne d .
The
right part
of
t rip
c i r cuit s and the
c ont r o l
circuit s .
The
paths
are :
First
z one - D and
z one - D,
Z2 and T2 ;
The
carri e r
c ont r o l led
through
D , Z 2 and
RRP
protect ion
a carrie r c ont ro l le d
is set up through
the c ontac t s Do and Io2
the ground re lay
and the
c ont act ,
RRG .
The
cont act
start carrie r .
The c ontact s , RRP and RRG, are
on the
b l ocking relay
rier s i gnal operating RRH and RRT c oi l s .
The c ontact s
Z 3
( A,
4
E TC.
and
two
instantane ous
The ope rat ion of the se
1.
in Fi��re
The
ha s a s ingle
c ontact
and dire ct
t ime r .
The same s cheme
third impedance
thi s
lat t e r
type
HZ
circuit
is shown
The f o l l owing d i s -
1
t o Figure
but ap
2 .
The t rip c i r
1
Figure
a s far a s car
Figure
1
c omp r i se s the
left part , the carrier
d i stance
type
t rip
Z l ;
Se cond
Third z one - D, and T3 .
t r ipping
path
i s
c ontact s .
For ground
t rip circuit
of
carrier
c ont ro l le d
Io3 i s used
t o
cont ro l le d by the car
C pha se s )
in the
B , &
left
part of
the
f igure serve
t ransmi s s ion
of carri e r f o r
c ontact Io3 performs the same funct i on f o r the
ground fau lt s .
The ground st art c ontact , Io3 ,
i s ope rat ed
by an ove r -current
rate
from that
which
c ontact .
Carrier i s started by c l o sing any one of the
carrie r
start c ontact s Z3 or Io3 , the carrier
t e st
push
but t on ,
or
start
c ontact s .
The se
p late
of the carrier o s c i l l at or tube t o p o s i
t ive .
The cathode
of the o s c i l lat or tube i s
c onne cted
t o
negat i ve
c ontact s
CSP
and
CSG
Carrier st opping i s c ont ro l led by the t r ipping
c ont act s ,
D
and Z 2 ,
and
Io2
for ground fau lt s .
f l ow s
int o
the
prot e cted
t r ipping
c ontact s ,
D
fault s
and permit
the coil of the
c ontactor swit ch ,
CSP, to be ene rgized .
cau s e s
the
back
CSP
c ont ro l
circuit s to ope n , which stops Jarrier
by rai s ing the cathode voltage above the ope r
at ing
value ,
and p e rmit s
c o i l of the re ceive r
re lay to be ene rgized by
the stat i on bat t ery .
Simi larly ,
f o r
ground
c l o se
t o ene rgize
the
l i ary contact o r
switch, CSG,
tact ,
.CSG,
s t op s
carrier and
ope rating
c o i l
of the
energized .
The arrangement
of
s t op c ircui t s i s such that opening CSP and CSG
c ontac t s
s t op carrier regard l e s s
r i e r i s start e d .
Thu s re laying has preference
at all
t ime s over all othe r
r i e r channe l .
The circui t s are arranged s o that the act ion
of
the ground
re l ay can be
over the
phase relay s .
nect ing the
c ont ac t s
HRP relay around CSP carrie r s t op
shown .
Thi s means
that if
relay st art s
carrier ,
for the
CSP c ontact
and the , pha se re lays t o
s t op carrie r .
The .purpo s e o f thi s ground pre -
t o start the
phas e fault s and
e lement sepa
operate s the
t r ipping
the auxi l iary carrier·
c ontact s � onne ct
the
through
the
back
1.
as shown in Figure
f o r pha se fault s and De
When fault power
l ine se ction , the
and Z 2 c l o se for pha se
auxil iary
Thi s
c ontact in the carrier
the
RRT operat ing
fault s
Do and
Io2
coil of another auxi
who se back c on
pe rmi t s
the
receiver re l ay to
be
the
carrie r
start and
of how car
use s of the car
given preference
Thi s is
d one by c on
CSO of the
type HRK or
c ontact s as
Io3 of the ground
it i s
then imp o s sible
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