Appendix C Specifications
Page 42
Overcurrent Timing Characteristics
Characteristic:
Time Dial :
Time Delay Accuracy
Instrumentation Feature
Communications Option
Power Supply
Target Indicators
Single-Phase Units:
Multi-Phase Units
Table C.1
Specifications (continued)
The relay incorporates all of the time overcurrent characteristics shown in
Figures A.1
through
A.1 6
in
Appendix A.
Selection of a specific timing characteristic is
accomplished by programmed instructions. Separate selections can be made for
phase current and for ground current.
Refer to
Figures A.1
through
A.1 6
in
Appendix A,
which show
1 4
of the
1 00
available
curves for each type.
The time overcurrent delay shall be within
5%
or
20
milliseconds (whichever is greater)
of the characteristic curves shown in
Figures A.1
through
A.1 6
in
Appendix A
for
any combination of TIME DIAL and pickup setting at
25°C.
The time delay shall not
vary more than +/-
5%
over the temperature range of
-40°
to
70°C (-40°
to
1 58°F)
Provision is made to monitor primary current on a real-time basis. Accuracy is within
+1-
2%. Range is from 1 0% of TAP (at the low end) to 1 50% of TAP (at the high end).
Includes an RS-232 port on the front panel for local testing and configuration, and an
RS-485 port at rear of unit for operation by a Siemens Power Monitor unit at distances
up to 4000 feet using baud rates up to 1 9,200.
Power for the internal circuitry may be derived from ac or de external power sources
as indicated in
Table C.2.
If ac control power is used, a separate power supply
hold-up circuit is required. (Option
3-1)
The targets are magnetically latched type.
Current-operated targets are furnished for each of the tripping outputs included within
the relay (e.g., TIME and INSTantaneous overcurrent functions)
To trip, a current-operated target requires a minimum of 0.2 A in the output circuit of
its associated output contact. This confirms that current has flowed through the relay
output contacts and the external trip circuit.
Includes the above plus an internally-operated target for each phase element (A,
B,
C,
and/or ground) which may initiate a trip.
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