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CARRIER RELAYING
CARRIER
NEG.
RECEIVER
TV
Fig. 3- Time Delay Circuit For The Carrier Alarm When
Using The Carrier Channel For Telemetering Or
Supervisory.
except directional control is omitted when
is reversed for Carrier
HZM relays.
HR?
The T ypes
HR¥ or
directional
element
and two
over-current elements.
elements is explained below.
The
s.chematic carrier control and trip cir
cuits are
shown
simplified in Figure 1.
Type HZM or HZ relay
shown here
third
impedance
element
ional
control
of the timer.
also can be used with the older type HZ relays
with
two
make and one
element contacts.
With
relay
the
carrier
control
schematically in Figure 2.
cussi0n
refers
directly
applie&
equally
well
circuits
using either· type HZ relay are basi
cally
the same as shown in Figure
carrier is concerned.
The
right
part
of
trip
circuits
and the left part, the carrier
control
circuits.
The
paths are:
First zone - D and Zl; Second zone
- D, Z2 and T2; Third zone
carrier controlled tripping path
D, Z2 and RRP contacts.
a carrier controlled
trip
4
POS.
T � TO TELEMETER
RECEIVER, ETC.
13-D-5623
Z3
when
using
the Type
ground relays
have a
instantaneous
The operation of these
The
has a single
contact and direct
The same scheme
break third impedance
this
latter type HZ
circuit is shown
The following dis
to
Figure l but
to Figure
2.
The trip
1
as far as
Figure l comprises the
distance
type
trip
D,
-
and T3.
The
is
through
For ground protection
circuit
is set up
through
the
contacts
relay and �he carrier controlled contact
The contact
IoS is used to start carrier.
contacts,
RRP
and RRG,
lay controlled by the carrier signal operating
RRH and RRT coils.
Z3 (A, B,
The
contacts
left part
of
the
figure
transmission
of
carrier for phase faults and
contact IoS performs the same function for the
ground faults.
The ground start contact,
is
by
operated
an over-current
a
which
rate from t
h
t
operates
contact.
Carrier is started by closing any one of the
carrier
start contacts Z3 or IoS, the carrier
test
push
button,
or
start
contacts.
These
plate
of the carrier oscillator tube to posi-
tive.
The rectifier
carrier start circuit
of
current
in
the control circuit resistors
which
would
unnecessarily
start contacts.
The cathode of the oscillator
tube is connected to negative through the back
contacts
CSP
and
CSG
Carrier stopping is controlled by the tripping
contacts, D and Z2,
for phase
and Io2
for ground
faults.
flows
into
the
protected
tripping
contacts, D and Z2
faults and
permit
the coil of the
contactor
switch, CSP, to be energized.
causes
the
back
CSP
control
circuits to open, which stops carrier
by
raising
the
cathode
operating value, and permits the RRT operating
coil
of the receiver relay to be energized by
the station battery.
Similarly, for ground faults Do and Io close
to
energize
the
coil
contactor
switch,
CSG,
CSG,
stops
carrier and permits the operating
coil of the receiver relay to be energized.
of
The
arrangement
stop circuits is such that opening
contacts
stop
carrier
is
Thus relaying has prefer-
carrier
started.
Do and
Io of the ground
RRG.
The
blocking
are on the
re
)
&
C
phases
in
the
serve to start the
IoS,
-
s
element
epa
the
tripping
the auxiliary carrier
contacts connect the
valves
in the relaying
are to prevent the flow
load
the carrier
as shown in Figure l.
faults and
Do
When fault power
line section, the
close
for phase
auxiliary
This
contact in the carrier
voltage
above the
of another
auxiliary
whose
back contact,
carrier
start
and
the
CSP and CSG
of
how
regardless
\.
,
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