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NEG.
CARRIER
RECEIVER
TELEPHONE AL
Figure 3
Time De l ay
Circuit
For the C arrier Alarm
Us ing the Carrier Channel
Supervis ory .
This
is s ignif i c ant in c a s e a line
c onnec t e d
from a s ourc e o f power a t one end ; i n
other word s ,
b e c ome s a s tub end
fault o c c ur s
on such a line,
mi t t er wi ll be s t arted
end whi ch is c onnec t ed
and no c arrier
will be
end to interfere with tr ipping .
On parallel line s ,
have the f ault power undergo a quick rever sal as
the breakers
on the faulted
this c ondition,
c arrier
tained at one end
unt i l it has
s tarted a t the other .
It is des irable
the c ondition
of the carrier
i t s ab i l ity to s end and rec eive a c arrier s ignal .
For this purpo s e a t e s t push button is c onne c ted
in paral l e l
with the
Pr e s s ing
the t e s t push
signal
whi ch is r e c e ived
a t both ends o f t h e line s e c t ion
alarm r e l ay
and energize
the c arr ier s et is not func t ioning, the alarm i s
n o t heard and the milliamme t er d o e s
indicat ing trouble
whi c h must
The alarm relay has a minimum operat ing value in
exc e s s
or the minimum required
r e c e iver r e lay so that an indication
ing trouble c an be obt ained
ure o c c ur s .
A thre e - p o l e sing l e - t hrow
erated from a c ommon handle
c arrier t r ip and out- of- s t ep c ir c ui t s ,
in Figure
l .
The switch is marked " C arrier On
off " and opening it removes
and permi t s t he · type HZ or HZM r e lays to operate
in the c onventional s t ep- z one manner . The switch
the types HRK or HRP ground
also removes
and ground pro t e c t i on i s availab l e through back
up gr ound relays .
OUT- OF- STEP PROTECTION
It i s often d e s irabl
operation or r e lays
during
t i ons so t hat the system c an b e s eparated at lo
c ations where synchroniz ing equipment
ab le .
The c arrier r e l aying
rneans
of prevent ing tripping during out- of- s tep
c onditions without impairing the ab i lity to trip
for internal faults o c c urr ing during out- of- s t ep
c ond i t ions .
One fundament al difference between
a three phas e fault and an out- of- s t ep c ondition
i s that a f ault suddenly reduc e s the vo ltage and
CARRIER RELAYING
TO TELEMETER
T�
RECEIVER, ETC.
When
For
T e lemetering
or
bec omes d i s
feeder .
I f
the c ar r i er trans
and stopped only at
the
t o the s ource
of
power
rec eived from the other
i t i s
p o s s ib le t o
line open .
Under
transmi s s ion i s main
had time
to b e
to 9heck periodic ally
set
to determine
c arrier
s t ar t
e lement s .
button sends
a c arrier
by the r e c e iver t ub e s
t o operate
a
milliamme t er .
n o t deflect
be inve st igated .
to operate
the
of impend
before actual fail
switch
op
i s c onnec ted in the
as shown
c arrier supervis ion
r e lay
e
t o prevent
the
out- of- s t ep
condi
is avail
system
provides a
POS.
inc r e as e s
the current .
proach of an out- or- s t ep c ondition,
and current c hange s a r e c omparatively gradual .
The typ e HZM r e lays
t o operate o n f ault s ,
chroni zing surge swings
c an rec over .
However, when the system g o e s out
of- s t e p ,
the type HZM r e lays operate t o separate
the system .
To provide out -of - step b l ocking in
the
Type
HZM
Carrier
b l o cking re lay
i s re quire d ,
T S0 - 3 out - o f - step b l o c king
I . L . 4 1 -4 1 8 . 3 .
I n the type HZ Carrier s cheme , out -of
step b l o c king
i s provided by u sing the type RSN
re l ay instead of the type RS re lay .
In
this
me nt s a l l
operate
phase fau l t if they are to operate at al l , wh i l e
during out -of -step
l owed by Z 2 and then Z l .
t oward the " in -phase " p o s it i on , the e lement s re
set in the opp o site orde r ; that , Z l , Z 2 , 23 .
• r o prevent tripping
a
st e p , i t i s ne ce s sary t o arrange f o r the c l o sure
of the three c ontac t s A , B , C ,
ce iver re lay bac� c ontact ,
addit i onal b l o c king re lay
cuit .
Thi s b l o cking re l ay
t ime -de l ay
so that
c ir cuit
before t r ipping
can o c cur ;
On the other hand , it mu st open the
t r ip c i rcuit during an out -of - step condition be
fore the s e c ond e lement , Z2 i s operated.
The out- of- s t ep
d e s ignated a s X2 ,
c ir c ui t as shown in Figure l.
i t ar e three c ontac t s , A, B ,
back c ont ac t s on the auxi liary swi t c h e s A, B,
operated by the Z3 c arrier s t ar t ing c ontac t s
the di stance r e lays thru the auxi liary c ontac tor
swi t c he s , C SA, C SB , and C SC .
of the s e swi t c h e s
c ontac t ,
RRB,
of the r e c e iver b locking
and energize
the c o i l ,
an
time- de lay re lay ,
If
energize
the
c o i l
Every t ime
that all
s t art c ontac t s c lo s e ,
and 'X2,
C ,
open the trip c ircuit after a 3 t o
Back c ont ac t X2 ,
cycle delay .
of all three rnake c ontac t s , A, B,
through RRB t o energize
the X2 c o i l .
If the e l e c t r i c a l
the pro t e c t e d line s e c t ion,
where the two voltag e s ourc e s appear 1 8 0 ° out of
pha s e , the direc t i onal and impedanc e e lement s at
each " end of the line wi l l b e c lo s e d .
c arrier ( previously s t ar t ed b y t h e Z3 c ont ac t
Thi s energi ze s RRT
tact RRB to open ,
lum r e lay, P ,
who s e spring
o s c i l late ,
alternately c l o s ing
top c ontac t s , P .
gized .
Af ter the amplitude
pendulum has decreas ed
wi ll not s trike either
wi ll r e s e t .
This a c t i o n o c curs
the time de lay introduced
should be longer t han the t ime during whic h both
direct ional e lements
upon the length of the
t em .
It is d e s irable
o c c urring during an out- of- s t ep
it is not so e s s ent ial
at high s peed .
The ground r e lay trip c ir cuit i s
not blocked
b y the out- of- step r e lay,
- 4 -
whereas during the
the v o l t ag e
are
usually
but no t
on load
or s yn
from whi ch
the
s cheme ,
an
add i t i ona l
such as
the
re l ay
de scribed
s cheme ,
the
di stance
simu l t ane ous ly
for a
the Z3 operat e s first ,
A s the system returns
during
out - o f
and f or the
RRB , t o
operate
to open the trip c i r
mu st have
a s l i ght
it doe s not open
the
on a three phase fau l t
b lo cking
c ontac t
and i s c onnec ted
i n the trip
In paral lel with
C,
whic h are
The make c ontac t s
are i n s er 1 e s
with the
P ,
of a pendulum
who s e lower c ontac t s make and
of the X2
b lo cking
three
of the
Z3
c arrier
the back c ontac t s ,
opens b y virtue
and C,
c lo s ing
the P c o i l and in turn,
c enter
is
and in other
This s t o p s
to allow the
Thi s de- energi z e s the pendu
arm
begins now
t h e b o t t om
Thi s keeps the X2 c o i l
of vibration of the
t o a c er t ain
value,
of i t s c ontac t s
and
in cyc le s , and
by the pendulum r e la
" :p, o int in"
which
depends
' s lip cyc l e "
of the sys
t o c le ar internal f aults
c o nd i t i on ,
to be able t o c lear them
X2 ,
ap
s e t
s y s t em
Type
in
e l e
three
f o l
re
an
t rip
i s
the
C ,
of
back
r e lay,
type
r e lay .
4
A , B
inside
c a s e s
)
.
c on
t o
and
ener
i t
X2
y
but
and
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