J.L. 41-610.1 c
INSTALLATION
•
OPERATION
•
MAINTENANCE
INSTRUCTIONS
TYPE HQS PHASE SELECTOR RELAY FOR
SELECTIVE-POLE CARRIER RELAYING
CAUTION
Before putting ·relays into service,
remove all blocking which may have been in
serted for the purpose of securing the parts
during
shipment,
make sure that all moving
parts operate freely, inspect the contacts to
see that they are clean and close properly,
and operate the relay to check the settings
and electrical connections.
APPLICATION
The type HQS relay operates on negative and
zero
sequence
currents to select the faulted
phase
occurs
when
on
a
the
single phase-to-ground fault
protected transmission line.
The zero sequence current is obtained from the
neutral
of the line current transformers, and
the negative sequence current from an external
three-phase filter supplied with the relay.
CONSTRUCTION AND OPERATION
The type HQS relay consists of three phase
selector elements,
three contactor switches,
and three operation indicators mourited in the
standard
case of Figure 4. The
external
three-phase
negative,
sequence
filter is
mounted in the case of Figure
3.
The oper
at·ion of this relay in the carrier scheme is
described in I.L. 41-600.2.
Phase Selector
The phase selector element is similar to the
H directional element as used in the type
HZ
and HRK-P relays.
The primary of a small cur
rent transformer receives the zero sequence
_component of line current which causes a large
current to flow in a one-turn movable aluminum
secondary.
Two other current
coils are
mounted on either side of a magnetic frame and
these coils receive the negative sequence com
ponent
of
line current from an external
SUPERSEDES I.L. 41-610.1 B
filter.
These zero and negative sequence
elements are assembled at right angle to each
other with the one-turn loop in the air gaps
of the negative sequence current coil flux
path.
The interaction of the two fluxes pro
duces torque and rotates the loop in a direc
tion depending on the relative instantaneous
direction of current flow in the two coils.
An
Isolantite arm extends from the moving
loop and supports a rectangular silver contact
which bridges two stationary contacts mounted
on either side of the loop. The stationary
contacts
on the
are
lower
silver conical surfaces mounted
end of vertically
hanging
springs. The contact separation is adjustable
by a small screw near the upper end of the
rigid
stationary contact supporting arm.
One
of these supporting arms hangs parallel to
each of the four stationary contacts.
The set
screw on the lower end of this arm provides
the contact follow adjustment.
Two additional
screws on the movement frame beneath
the
negative sequence coil iron limit the movement
of the loop.
There are three of these phase
selector elements,
one for each of the three
phases and designated SA, SB and
s0
for phases
A, B, and C respectively. The sub numbers
2
and
0
indicate the negative and zero sequence
coils.
Contactor Switch
The d-e. contactor switch in the relay is a
small solenoid type switch.
A cylindrical
plunger with a silver disc mounted on its
lower end moves in the core of the solenoid.
As the plunger travels upward,
the
disc
bridges three silver stationary contacts.
The
coil is in series with the main contacts of
the relay and with the trip coil of the
breaker.
When the relay contacts close, the
coil becomes energized and closes the switch
EFFECTIVE FEBRUARY 1949
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