Features • Fail-safe sequential disconnection of
current, voltage and trip circuits when the
test-plug handle is inserted.
• Latching feature when the test-plug handle
is withdrawn allowing the relay to stabilize
with service values before the trip circuits
are restored. This prevents inadvertent tripping.
• Complete isolation of secondary instrument
transformer circuits.
• Trip-block plug which isolates a trip circuit
without interrupting other circuits, allowing
the trip output to be monitored, and also
provides visual indication of an isolated trip
circuit.
• Block-plug handle which disconnects all
circuits routed through the test switch.
• Ammeter test-plug with local automatic
short-circuiting device in case of inadvertent
opening of a CT circuit.
• Auxiliary station power supply made
available for test equipment.
• Extension bases which facilitate
measurement and adjustment of plug-in
module circuits.
Application The COMBITEST system for testing of protection
relays is built up around the RTXP 8,
RTXP 18 or RTXP 24 test switches. The test
switch can also be used for other testing
needs not directly associated with relays,
such as for switchboards or voltmeters.
The test switch may be used where testing
would otherwise require disconnection of the
instrument transformer’ s secondary or control
wiring. It may also be used to advantage in
the testing of other complete relay systems,
even when each individual relay has its own
test switch.
When the test-plug handle is inserted into the
test switch, preparations for testing are automatically
carried out in the proper sequence,
i.e. blocking of tripping circuits, short-circuiting
of CT’ s, opening of voltage circuits, making
relay terminals available for secondary
injection.
The test-plug handle may be connected to any
type of test equipment or instrument. When a
number of protection relays of the same type
are tested, the test-plug handle need to be
moved only from the test switch of one relay
to the test switch of the other, without altering
previously made connections. If different
types of relays are to be tested, it is a simple
matter to change the connections on the testplug
handle and the relay testing set. |