7PG21 Solkor Rf Commissioning
©2012 Siemens Protection Devices Limited
Chapter 6 Page 19 of 21
4.2.3 Injection intertripping - Solkor-R & Solkor-Rf
Injection intertripping is used where decisive intertripping is required, irrespective of the current in the protected
feeder, and to avoid possible interaction between the injected signal and power frequency voltages. Its use also
avoids the requirement for 5kV or 15kV insulated intertripping batteries.
Injection intertripping is not suitable for use with guard relays (which place normally open contacts in series with
the Solkor relay contact) or for Solkor-R with Supervision applied to the same pilots, (for such schemes
Supervision may be carried out over spare cores). Due to a different inverter being required, Solkor-Rf can use
both injection intertripping and supervision over the same pilots.
The send equipment comprises an inverter and a type TEC relay to switch the a.c. intertripping signal, Solkor-Rf
requires an additional time delay relay. The receive relay is the remote Solkor relay. It is unnecessary to
continuously energise the inverter, normally a full power signal is sent for 2 secs, followed by either de-
energisation of the inverter or by a reduced inverter output which holds the remote relay operated, see fig 10.
Note applicable to all schemes:
-
Where contacts are directly connected to the pilot wires then 5kV/15kV isolation must be maintained from earth
and other circuits.
Fig 10. Typical 2 stage sustained intertripping scheme for Solkor –Rf. Send End.
