Siemens Reyrolle 7SR46 - Power Options; Overview; Auxiliary Power Supply; CT Input

Power Options
Overview
The 7SR46 Argus Relay can be powered on by using the following sources:
•
Auxiliary power supply
•
CT input
•
USB power
•
Battery
The 7SR46 Argus relay is powered primarily from auxiliary power supply even if all other power sources are
available. In the absence of auxiliary power supply, the relay is powered through phase currents. It is also
referred to as CT power.
In the absence of both auxiliary power and phase currents, the relay is powered on by USB power or battery.
In the absence of auxiliary power supply, phase currents, and USB power, the relay can be powered on by
battery only.
Table 6-1 Peripheral Operations in Different Power Sources
Power Source Peripherals Operational
Auxiliary Power Supply Binary input, binary output, pulse output, remote flag, local flag, LED,
external trip input, RS-485 communication, LCD backlight
CT Input Binary input, binary output, pulse output, remote flag, local flag, LED,
external trip input
1
, RS-485 communication
1
, LCD backlight
1
USB Power
Binary input, binary output, LED, LCD backlight, pulse output
2
, remote
flag
2
, and local flag
2
Battery Binary input, binary output, LED, LCD backlight, resetting local flag
Auxiliary Power Supply
When the 7SR46 Argus Relay is powered with auxiliary power supply, all the protection and measuring algo-
rithms and RS485 communication (Rear port) are active.
CT Input
When the 7SR46 Argus Relay is powered through phase current transformers and the auxiliary voltage is
absent, all the protection and measuring algorithms are active 0.8 ⋅ I
smin
(1-phase) and 0.4 ⋅ I
smin
(3-phase).
RS485 communication is operational when current above 1.62 ⋅ I
smin
(1-phase) or 0.6 ⋅ I
smin
(3-phase).
Table 6-2
Minimum Current Requirements for Peripheral Operations in Self-Powered Mode
Peripherals 1-Phase (⋅ I
smin
) 3-Phase (⋅ I
smin
)
Binary output, binary input,
pulse output, flag output,
local flag, and external trip
input
0.8 0.4
RS-485 communication 1.62 0.6
LCD Backlight - 1.62
6.4
6.4.1
6.4.2
6.4.3
1
Refer to 6.4.3 CT Input for corresponding current ratings.
2
Is operational only under Maintenance menu.
In Service Operation
6.4 Power Options
Reyrolle, Operating, Manual 57
C53000-B7040-C103-1, Edition 10.2022