Pulse Output; Remote Flag Output; Modes Of Operation; Auxiliary Voltage - Siemens 7SR45 Argus User Manual

3.14 Pulse Output

The pulse output is used to interface directly with the low energy circuit breaker tripping coil. The pulse output
provides 24 V, 0.1 Ws pulses of 50 ms ON and 500 ms OFF.
The pulse output operates when any configured protection function trips. The trip energy for the trip coil is stored
by a capacitor built into the protection relay. The capacitors are charged by the auxiliary power supply/phase
current. The pulses are repeated until the fault current falls below the set value. The pulse output does not require
any mapping with protection functions.
In the presence of auxiliary power supply/phase current, pulse output can be operated by mapping to a binary
input. When the assigned binary input is triggered, the pulse output operates, local flag operates, and Trip LED
flashes. Pulse output is provided till the auxiliary power supply/phase current is available.
NOTE:
The time between the two pulses depends on the impedance of the trip coil and magnitude of the current (if the
relay is powered through phase currents).
When there is NO LOAD connected at the output of Pulse Output (NO TRIP coil is connected), the PULSE ON
duration may vary from 50 ms to 70 ms.
Pulse output cannot be triggered through Rear/Front communication protocols, it is recommended to use BIs for
triggering the pulse output for remote trip applications.

3.15 Remote Flag Output

The remote flag output is used to indicate the trip via an external flag. The remote flag output provides 24 V,
0.01 Ws pulses of 50 ms ON and 500 ms OFF.
The remote flag output operates when any protection function trips. The energy is stored by a capacitor built into
the protection relay. The capacitor is charged by auxiliary voltage or phase current. The pulses are repeated until
the fault current falls below the set value. The remote flag output does not require any mapping with protection
functions.
NOTE:
The time between the two pulses depends on the impedance of the flag indicator and on the current level (if the
relay is powered by auxiliary power/phase current).

3.16 Modes of Operation

The 7SR45 Argus Relay can be powered on by using the following sources:
• Auxiliary Voltage Inputs
•

CT Input

• USB
• Battery
The 7SR45 Argus Relay is powered primarily from auxiliary voltage even if all other power sources are available.
In the absence of auxiliary voltage, the relay is powered through phase currents.
In the absence of both auxiliary voltage and phase currents, the relay can be powered on by USB or battery.
The relay can be powered on by the battery only if all other power sources are not available.

3.16.1 Auxiliary Voltage

All the protection and measurement algorithms and RS485 communication (Rear port) are active when the 7SR45
Argus Relay is powered by auxiliary voltage.
NOTE:
In the absence of auxiliary voltage, the binary output 3 and binary output 4 will not be functional and remain in the
non-operated conditions.
3.16.2 CT Input
In the absence of auxiliary voltage, all the protection and measurement algorithms are active when the 7SR45
Argus Relay is powered through phase CTs, however the RS485 communication stops working.
3.16.2.1 Sensitivity
In the absence of auxiliary voltage, the sensitivity of the relay is the minimum phase current required for the relay
to energize, detect a fault, and trip as per the configuration.
©2018 Siemens Protection Devices Limited
Chapter 1 - 7SR45 Description of Operation
Chapter 1 Page 41 of 48