Modes Of Operation; Overview; Auxiliary Voltage; Ct Input - Siemens 7SR45 Manual

6.4

Modes of Operation

Overview

6.4.1
The 7SR45 Argus Relay can be powered on by using the following sources:
•
Auxiliary voltage input
•

CT input

•
USB
•
Battery
The 7SR45 Argus Relay is powered primarily from auxiliary voltage even if all other power sources are avail-
able. 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.
In the absence of auxiliary voltage, phase currents, and USB, the relay can be powered on by battery only.
NOTE
i i
The auxiliary voltage input source is not available for MLFB 7SR450[1/3]-xGA10-1AA0 variant.
6.4.2

Auxiliary Voltage

When the 7SR45 Argus Relay is powered with auxiliary voltage, all the protection and measuring algorithms
and RS485 communication (Rear port) are active.
NOTE
i
i
In the absence of auxiliary voltage, the binary output 3 and binary output 4 do not function and remain in
the non-operated conditions. RS485 communication is also not available in the absense of auxiliary power.
6.4.3 CT Input
When the 7SR45 Argus Relay is powered through phase current transformers and the auxiliary voltage is
absent, all the protection and measuring algorithms are active and the RS485 communication is not opera-
tional.
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.
The sensitivity of 7SR45 Argus Relay is 0.20 ⋅ I
(minimum phase current) in 3-phase. This minimum phase current is necessary for the healthy functioning of
the relay.
The protection healthy and trip ready LEDs indicate the status of the relay.
The following graphs show the sensitivity of the relay and the corresponding operating time for different
startup currents.
Reyrolle, Operating, Manual
C53000-B7040-C101-1, Edition 08.2020
(minimum phase current) in 1-phase or 0.10 ⋅ I
rated
In Service Operation

6.4 Modes of Operation

rated
67