C-415EM
INSTRUCTION MANUAL
DSP-CA(S) CABLE ADAPTER
April 2007
2
1. Introduction
1.1. The DIN –Rail mounted DSP Ground Fault Protection system from IPC Resistors is used exclusively with
High-Resistance Grounded (HRG) power systems. The DSP can be used on multi-source substations such
as double-ended main-tie-main board arrangements. In the case of a utility outage on one of the sources of
such a system, the main breaker on one side will open and the tie breaker will close (through key interlock
or other controls) so that power on the ‘dead’ side is supplied from the ‘live’ side to maintain service to both
sides of the board.
1.2. The DSP system includes priority allocation to each feeder breaker depending on its importance. On a
double-ended station there will be two DSP systems – one on each side of the board. Normally they will
operate independently of each other. However, when the tie breaker is closed the two DSP systems will not
prioritize breakers on the other side of the board and in the event of a fault involving both sides of the board,
then two breakers would trip.
1.3. To prioritize the combined system it is possible to join the two priority buses together when the tie breaker is
closed using an 8-conductor shielded cable. The cable can connected at either end through IPC cable
adapter modules types DSP-CA or DSP-CAS.
1.4. The DSP-CA and DSP-CAS are similar 70mm DIN rail mounted units that tie into the DSP system with
standard 20 position ribbon cable connectors (IPC Resistors RC-3) the 8-conductor cable then may be
connected to either an 8-position terminal block or plugged into a RJ-45 8-8 Modular Jack at the discretion
of the installer. The DSP-CA and DSP-CAS modules simply act as junction boxes to connect the priority bus
lines to the appropriate ribbon cable terminals.
1.5. The DSP-CAS includes an electronic switch to connect or disconnect the priority bus from the DSP bus.
This switch is controlled by a contact closure across the two input terminals (1 and 2). A yellow ON LED
indicates that the switch is activated.
1.6. The DSP-CA module is simply a junction box without switching. One of each module is required to interface
the cable to the DSP Modules.
Note: A DSP-CAS can be used instead of a DSP-CA if necessary, but the input terminals would have to be
permanently shorted
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